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AL 8 



The late Professor E. A. Minchin, M.A., F.R.S. 



Frontispiece] 



[See page 669 






THE JOURNAL 



OF THE 



(fyukttk 

Microscopical Club 



EDITED BY 
A. W. SHEPPARD, F.Z.S., F.R.M.S. 



SECOND SERIES. 

VOLUME XII. 



1913-1915. 



.--.._ 




... 



[Published for the Club] 

WILLIAMS AND NORGATE, 

14. Henrietta Street, Covent Garden. London, 
and 7, Broad Street, Oxford. 



PRINTED BY 
HAZELL, WATSON AND VIXEY, LD., 
LONDON' AND AYLESBURY. 



Ill 



C O N T E N T S . 



PART No. 72. APRIL 1913. 



Papers. 

E. Heron-Allen. F.L.S., F.R.M.S., awl A. Euiland, F.R.M.S. 
The Foraminifera in their Role as World- builders : A 
Review of the Foraminiferous Liiw stones and Other Rocks 
of th^ Eastern and Western Hemispheres (Plates 1-3) 

W. M. Bale, F.R.M.S. Notes on Some of the Discoid Diatoms . 

Henry Whitehead, B.Sc. Some Notes on British Freshwater 
Rhabdocoelida a Group of Turbellaria (Plate 4) 

Charles F. Rousselet, F.R.M.S. The Rotifera of Devils Lake, 
with Description of a New Brachionus (Plates 5 and (3) 

Arthur Dendy, D.Sc, F.R.S. President's Address By- Pro- 
ducts of Organic Evolution (Plate 7) . 

David Bryce. On Five New Species of Bdelloid Rotifera (Plates 
8 and 9) ........ 

Notes. 

E. M. Nelson, F.R.M.S. A New Low-power Condenser 

E. M. Nelson. F.R.M.S. Xavicula rhomboides and Allied Forms 

E. M. Nelson, F.R.M.S. On Microscope Construction and the 

Side Screw Fine Adjustment (Figs. 1 and 2 in text) 
E. M. Nelson, F.R.M.S. Note on Pleurosiqma angukitum (Figs. 

3 and 4 in text) ........ 

E. M. Nelson, F.R.M.S. Actinoci/clus Ralfsii and a Coloured 

Coma .... ..... 

Notices or Books ........ 



PAGH 



1 

17 
4.3 
57 
05 

83 



95 
90 

90 

98 

100 
101 



Proceedings, etc. 

Proceedings from October 22nd, 1912, to February 25th, 1913, 
inclusive ......... 

Forty-seventh Annual Report, 1912 r 

Report of the Treasurer. 1912 . 



103 
113 

120 



PART No. 73, NOVEMBER 1913. 

Papers. 

E. Heron-Allen, F.L.S., F.G.S., F.R.M.S., and A. Earland, 
F.R.M.S. On some Foraminifera from the North Sea, 
dredged by the Fisheries Cruiser " Huxley " (International 
North Sea Investigations England) (Plates 10 and 11) . 



12 1 



'\J 



- 



IV CONTENTS. 

PACK 

C. D. Soar, F.L.S., F.R.M.S. Description of Arrhenurus Scour- 
fieldi and Acercus longitarsus, Two New Species of Water- 
mites (Plates 12 and 13) 130 

G. T. Harris. The Collection and Preservation of the Hydroida 143 

T. A. O'Donohoe. The Minute Structure of Coscinodiscus 
asteromphalus and of the Two Species of Pleurosigma, 
P. angulatum and P. balticum . . . . .155 

Henry Sidebottom. Lagenae of the South-West Pacific Ocean 

(Supplementary Paper). (Plates 15-18) . . .101 

James Murray, F.R.S.E. Gastrotricha (Plate 19) . . 211 

Notes. 

Edward M. Nelson, F.R.M.S. On a New Method of Measuring 

the Magnifying Power of a Microscope . . ,239 

Proceedings, etc. 

Proceedings from March 25th, 1913, to June 24th, 1913 . 245 

Obituary Notice : Rt. Hon. Sir Ford North, F.R.S., F.R.M.S. . 258 

PART No. 74. APRIL 1914. 
Papers. 

Arthur Dendy, D.Sc, F.R.S. President's Address Organisms 

and Origins ........ 259 

S. C. Akehurst, F.R.M.S. A Changer for Use with Sub-stage 

Condensers (Figs. 1 and 2) . . . . . .277 

S. C. Akehurst, F.R.M.S. A Trap for Free-swimming Or- 
ganisms (Fig. 3) . . . . . . . . 279 

E. M. Nelson, F.R.M.S. An Improved Form of Cheshire's 

Apertometer (Fig. 4) . . . . . . .281 

F. J. Cheshire, F.R.M.S. Two Simple Apertometers for Dry 

Lenses (Figs. 5 and 6) ..... . 283 

M. A. Ainslie, R.N.. B.A., F.R.A.S. A Variation of Cheshire's 

Apertometer (Figs. 7 and 8) . . . . . 287 

James Burton. On the Disc-like Termination of the Flagellum 

of some Euglenae . . . . . . 29 J 

E. M. Nelson, F.R.M.S. On the Measurement of the Initial 

Magnifying Powers of Objectives (Fig. 9) . . . 295 

S. C. Akehurst, F.R.M.S. Some Observations concerning Sub- 
stage Illumination (Plates 20-22) . . . .301 
T. A. O'Donohoe. An Attempt to Resolve and Photograph 

Pinnularia nobilis ....... 309 

N. E. Brown, A.L.S. Some Notes on the Structure of Diatoms 

(Plate 23) 317. 

Notes. 

James Burton. On a Method of Marking a Given Object for 

Future Reference on a Mounted Slide. . . .311 



CONTENTS. V 

Vk v. 
}). M. DRAPER. A Live Box for the Observation of Insects and 

Similar Objects ........ 313 

15. M. Draper. Dark-ground Illumination with the Greenough 

Binocular ...... 313 

E. M. Nelson. F.R.M.S. Amphvpleura Lindheimeri . . 315 

Notices of Books ........ 339 

Proceedings, etc. 

Proceedings from October 2Sth, 1013, to February 24th. 1914. 

inclusive ......... 340 

Forty-eighth Annual Report, 1913 314 

Report of the Treasurer, 1913 302 

List of Members . ...... i xxxii 

PART No. 75. NOVEMBER 1914. 

Papers. 

Edward M. Nelson. F.R.M.S. A New Object Glass by Zeiss. 

and a New Method of Illumination (Figs. 1-3) . . . 3 

Edward M. Nelson. F.R.M.S. A New Low-power Condenser 

(Fig. 4) 367 

Edward M. Nelsox. F.R.M.S. Binocular Microscopes (Fig. 5) . 309 

A. E. Hilton. Notes on the Cultivation of Plasmodia of Badhamia 

utricularis (Fig. 0) ...... 381 

A. A. C. Eliot Merlin, F.R.M.S. On the Minimum Visible . 385 

C. F. Rousselet, F.R.M.S. Remarks on Two Species of African 

Volvox 393 

C. F. Rousselet, F.R.M.S. Report on the Conference of Dele- 
gates of Corresponding Societies (British Association) held 
at Havre ......... 395 

( '. F. Rousselet, F.R.M.S. Pedalion ou Pedalia ; une question 

de nomenclature dans la classe des Rotiferes . . .397 

Proceedings, etc. 

Additions to the Library since January 1914 . . . 399 

Additions to the Club Cabinet since October 1912 ... . 401 

Proceedings from March 24th to June 23rd. 1914, inclusive . 411 

Obituary Notice : Dr. M. C. Cooke 422 

Table for the Conversion of English and Metrical Measures . . 424 

PART No. 76, APRIL 1915. 

Papers. 

R. T. Lewis. F.R.M.S. The Early History of the Quekett 

Microscopical Club . . . . . . 42 ~> 

D. J. Scourfield. F.Z.S., F.R.M.S. A New Copepod found in 

Water from Hollows on Tree Trunks. (Plates 24 and 25) 431 



VI CONTENTS. 



PAGE 



E. A. Minchin, M.A., F.R.S. Some Details in the Anatomy of the 

Rat Flea (Ceratophyllus fasciatus). (Plates 26-32) . .441 

Arthur Dendy, D.Sc., F.R.S. President's Address. The Bio- 
logical Conception of Individuality .... 465 

W. Williamson, F.R.S.E., and Charles D. Soar. F.L.S., 
F.R.M.S. British Hydracarina : The Genus Lebertia. 
(Plates 33 and 34) 479 

J. W. Gordon. A " New " Object Glass by Zeiss (Figs. 1 and 2) 515 

G. T. Harris. Microscopical Methods in Bryological Work . 52 ! 

Proceedings, etc. 

Proceedings from October 27th, 1914, to February 23rd, 1915, 

inclusive . . . . . . . . .537 

Forty- ninth Annual Report, 1914 . . . . . .551 

Report of the Treasurer, 1914 . . . . . . 558 

Obituary Notice : F. W. Millett, F.G.S., F.R.M.S. . . . 559 

PART No. 77, NOVEMBER 1915. 

Papers. 

M. A. Ainslie, R.N., B.A., F.R.A.S. An Addition to the Ob- 
jective (Figs. 1 and 2) ..... 561 
A. A. C. Eliot Merlin, F.R.M.S. Notes on Diatom Structure . 577 
G. T. Harris. A Note on the Slides of Fissidentaceae in the 

Q.M.C. Cabinet 581 

A. E. Hilton. Further Notes on the Cultivation of Plasmodia 

of Badhamia utricularis ...... 585 

James Burton. Hydrodictyon reticulation .... 587 

E. M. Nelson, F.R.M.S. Various Insect Structures . . . 593 

J. W. Evans, D.Sc, LL.B. (London). The Determination of 
Minerals under the Microscope by means of their Optical 

Characters (Plates 35-37) 597 

David Bryce. On Five New Species of the Genus Habrotrocha 

(Plates 38 and 39) 631 

Notices of Books (Plate 40) ...... 643 

Proceedings, etc. 

The Club Cabinet, Additions to . . . . .646 

Proceedings from March 23rd to June 22nd, inclusive . . 653 

Obituary Notice : E. A. Minchin, M.A., F.R.S. (Portrait) . 669 

Index to Volume XII. . . . . . . . 673 



Vll 




LIST OF ILLUSTRATIONS. 



PLATES. 

Portrait of the late Prof. E. A. Minchin. M.A., F.R.S., Facing page 501 

1-3. Foraminiferal Limestones. 

4. Rhabdocoelida. 

5. Asplanchna Silvestrii Daday. 

6. Rotifera. 

7. Spicules of Tetraxonid Sponges. 

8, 9. New Species of Bdelloid Rotifera. 

10. Foraminifera from the North Sea. 

11. Cornuspira diffusa Heron- Allen and Earland. Sand Grains, 

etc., from the Bottom Deposits. 

12. <$ Arrhenurus Scour fieldi sp. nov. 

13. q Acercus longitarsus sp. nov. 

14. Structure of Pleurosigma bait ten m. 

15-18. Lagenae of the South-West Pacific Ocean. 

19. Gastrotricha. 

20. View of Back Lens of Objective with P. angulatum in focus. 
21, 22. Resolution with Annular Illumination. 

23. Structure of Diatoms. 
24, 25. Moraria arboricola sp. nov. 
26-32. Anatomy of the Rat Flea. 
33, 34. The Genus Lebertia. 
35-37. Examination of Minerals. 
38, 39. Xew Species of Habrotrocha. 

40. Rhizopoda. 

FIGURES IN THE TEXT. 

Page 98. Side-screw fine adjustment. 
,, 99. Upper and lower membranes in P. strigusum and P. balti- 

cum. 
277. A changer for sub-stage condensers. 

,, 280. A trap for free- swimming organisms. 

,, 281. An improved form of Cheshire's Apertometer. 

,, 285. Two simple apertometers for dry lenses. 



VJ11 LIST OF ILLUSTRATIONS. 

Page 288. A variation of Cheshire's Apertometer. 
- j 8J. ,, ,, ,, 

298. The measurement of the initial magnifying power : diagram 

to show relative position of apparatus. 
32Q. Structure of pores in P. balticum according to O. Miiller. 
365. Diagram showing method of illumination. 

oOO. ,, ,, ,, ,, 

3C8. Centring stop-holder. 

374. Diagram of eye and Ram~den disc. 

383. Exhibition of plasmodia. 

517. Diagram illustrating a " new " object-glass. 

" 10 ' J ? ? > 

567. An addition to the objective : diagram. 
504. Various insect structures. 



-3 






THE JOURNAL : V 

OF THE 

<iuhcii $$t c rose opt cal dDInIr 

THE FORAMINIFERA IN THEIR ROLE AS WORLD- 
BUILDERS: A REVIEW OF THE FORAMINIFEROUS 
LIMESTONES AND OTHER ROCKS OF THE 
EASTERN AND WESTERN HEMISPHERES. 

By Edward Heron-Allen, F.L.S., F.R.M.S., axd 
Arthur Earland, F.R.M.S. 

{Read October 22nd, 1912.) 

Plates 1-3. 

" Life , as we call it, is nothing but the edge of the boundless Ocean of 
Existence where it comes on Soundings." 0. W. Holmes, The Pro- 
fessor, V. 

Our late President, Prof. E. A. Minchin, F.R.S., in his last 
Presidential Address * dealt with certain organisms which he 
regarded as the simplest existing living structures, and speculated 
on the Origin of Life in this planet. Subsequently at the British 
Association Meeting at Dundee he led a most interesting dis- 
cussion on the same subject, a discussion which left those who 
had the privilege of listening to it convinced of one fact at least, 
viz. that no two of the eminent men who took part in the debate 
were agreed on any single point. But as the earliest forms 
of life were necessarily of such a simple nature that they could 
oy no possibility have been preserved as fossils, the interest 
of geologists may almost be said to commence with the stage 
in which life had become endowed with a sufficiently complex 
structure to leave recognisable remains in the geological record. 

The Foraminifera would seem to constitute such a group. Of 
extremely simple structure, mere protoplasm without differenti- 
ation other than the nucleus, they yet possess the power either 
of secreting a solid shell from the mineral salts absorbed from 

* Journ. Q.M.C., Ser. 2, Vol. XI. p. 339. 
Jourx. Q. M. C, Series II. No. 72. 1 



*) 



E. IIIRON-ALLEN AND A. EARLAND ON THE FORAMINIFERA 



their surrounding medium, or'of building up adventitious shells 
by the co-ordination of foreign material obtained from their 
immediate environment. These shells, from their minute size 
and composition, are peculiarly adapted for preservation as 
fossils. 

Hence, whatever the origin of life may have been, we might 
reasonably expect that among its earliest records would occur 
Foraminifera of simple and ancestral types, and that subsequent 
geological periods would show a constant progression in their 
development. Such, however, is not the case. So far as our 
geological knowledge carries us at present, the Foraminifera 
make their first appearance in the rocks in a highly differentiated 
stage, and among the earliest recognisable groups are many species- 
which are still existing and dominant types to-day. 

It is not so very many years, less than half a century in fact, 
since the sensational discovery of Eozoon Canadense (1) (2) (3) in 
the Laurentian rocks of Canada was hailed as evidence that the 
oldest fossil was, as might have been expected, a rhizopod. Into 
the long warfare which was waged round this fossil, in which the 
late Prof. K. Mobius took an active part (22), it is not proposed 
to enter in detail. But there was at the time of its discovery 
no greater authority on the Rhizopoda than the late Dr. W. B. 
Carpenter, a former President of this Club. He threw the whole 
weight of his authority into the scale in favour of the foramini- 
feral nature of Eozoon, and to the last was convinced of the 
soundness of his belief. But the balance of evidence has turned 
against him, and since his death but little interest has been 
shown in the question, Eozoon having been relegated by more or 
less general consent to the mineral kingdom. 

We are, however, again threatened with a renewal of the 
controversy, for Mr. It. Kirkpatrick, of the British Museum, 
has recently announced in Nature that he is in possession of 
fresh evidence of the foraminiferal nature of Eozoon, and will 
shortly publish it. The microscopical world will no doubt await 
this evidence with interest, not unmixed, perhaps, with some 
trepidation at the reopening of this chose jugee. From the point 
of view of the subject of our paper, viz. " The Foraminifera as 
World-builders," definite proof of the rhizopodal nature of 
Eozoon would be very welcome. Eozoon, whatever its nature 
may be, occurs in enormous reefs in the Laurentian rocks of 



IN THEIR ROLE AS WORLD-BUILDERS. 3 

Canada and elsewhere, and we should thus have evidence that 
even at this early stage of the world's history, the Foraminifera 
had commenced to play that important part in the formation 
of strata which they have continued in nearly all the successive 
periods of geological history, and which is still proceeding in 
the deep sea to-day. It is no exaggeration to say that, in 
spite of their diminutive size, the Foraminifera have played, 
and are still playing, a greater part in building up the crust 
of the earth than all other organisms combined. 

Dismissing Eozoon for the present as incertae sedis, we find 
that the only other pre-Cambrian records which can be associated 
with Foraminifera are the peculiar bodies described by Cayeux (4) 
from certain quartzites and pthanites of the pre-Cambrian strata 
of Brittany. These are, however, of such minute size compared 
with other Foraminifera that their nature cannot be accepted 
on the evidence hitherto available. 

It appears, therefore, that at present we have no unquestionable 
records of Foraminifera in pre-Cambrian rocks ; but it is quite 
possible that such discoveries may be made in the future, as fossils 
of a higher type have been found, and it seems unlikely that 
Foraminifera did not, or could not, exist in seas capable of 
supporting such higher forms of life. 

When, however, we come to the Cambrian strata we find the 
Foraminifera flourishing, and already marked by numerous widely 
separated types. So long ago as 1858 Ehrenberg (5) figured 
some internal glauconitic casts of Foraminifera from a clay near 
St. Petersburg, which is known to be of Lower Cambrian age. 
According to Chapman (9) these casts are referable to at least 
five genera, viz. Verneuilina and Bolivina (family Textularidae), 
Nodosaria (family Lagenidae), Pidvinulina and Rotalia (family 
Rotalidae). 

Now it is noteworthy that none of these genera are of simple 
or primitive types, but are all comparatively complex in the 
arrangement of their chambers, and representing three distinct 
types of construction. Hence in this earliest geological record 
we find the group already well established, and markedly 
differentiated in structure. No monothalamous or primitive 
type appears in this earliest list, although we may be sure 
that they must have been in existence, both then and during 
antecedent ages. 



4 E HERON-ALLEN AND A. EARLAND ON THE FORAMTNIFERA 

Since the time of Ehrenberg there have been other discoveries 
of Cambrian Foraminifera in America (6) (7) and Siberia (8). 
We have not had an opportunity of seeing either of these reports, 
but it may be noted that the New Brunswick rocks furnished 
representatives of the pelagic genera Orbulina and Globigerina 
(family Globigerinidae), while the Siberian rock is described as 
assuming an oolitic structure on account of the numerous Fora- 
minifera which it contains. It is therefore apparent that the 
Foraminifera had already assumed that dominant position which 
they have ever since maintained in the biology of the sea. 

Turning to our own country, the oldest Foraminifera yet 
recorded are those described by Chapman (9) from a limestone 
of Upper Cambrian age near Malvern (PI. 1, fig. 1). This record is 
'of great interest because all the Foraminifera described are either 
monothalamous (genera Lagena, SpiriUina) or polythalamous 
shells of simple type (genera Nodosaria, Marginulina, Cristel- 
laria). As will be seen from the rock section figured by Chapman, 
the Foraminifera of one genus, SpiriUina, form a considerable 
proportion of the entire mass of the rock (PI. 1, fig. 1). The other 
species described are stated to have been of very rare occurrence. 
Now SpiriUina is one of the simplest conceivable types of rhizo- 
podal shell structure, an undivided tube coiled on itself in one plane, 
iand is theoretically one of the forms which might be expected 
to turn up in the earliest records. Chapman has on certain 
minor points of structure instituted a new species {SpiriUina 
Groomii Chapman) for this Cambrian type, but it appears to 
be nothing more than a variety of SpiriUina vivipara Ehrenberg, 
a species which at the present day occurs on muddy bottoms 
of moderate depth in all parts of the world.* So far as we 
are aware, however, there is no other record of its occurrence 
in sufficient abundance to form a noticeable constituent of any 
deposit, recent or fossil. In recent dredgings it cannot be 
described as an abundant species. 

In the next period, the Silurian, there are many records (10) 
(11) (12) (13) of Foraminifera, but they do not appear to be 
numerous. Brady (12) records and figures four species of the 

* Since this was written specimens resembling SpiriUina Groomii (Chap- 
man) have been found in dredgings made in Blacksod Bay, Co. Mayo, and 
also in the Moray Firth. They will be described and figured in the 
forthcoming report on the Foraminifera of the Clare Island Survey. 



IN THEIR ROLE AS WORLD-BUILDERS. 5> 

simple type Lagena, which are still existing, and of world-wide 
distribution. These and the Spirillina Groomii of Chapman 
(= S. vivipara Ehrenberg) are therefore probably the oldest 
living types now in existence. 

Of greater interest is the recording by Chapman (14) and 
Vine (15) of two genera of arenaceous Foraminifera, viz. Hyperam- 
mina and Stacheia from rocks of the Wenlock series. These 
constitute, so far as we are aware, the earliest evidence of the 
existence of arenaceous Foraminifera. The geological record 
does not furnish any evidence in support of the theory, so fre- 
quently postulated, that the earliest Foraminifera were types 
Avith adventitiously constructed tests \ nor do we see any reason 
for accepting this theory. The property of secreting mineral 
salts from the surrounding medium is common to organisms of 
all grades, whereas the power of selecting and utilising foreign 
material seems to indicate a later and higher stage of develop- 
ment. There appears to be no geological reason why the 
composite tests of arenaceous Foraminifera should have escaped 
fossilisation, when the delicate shells of -calcareous genera were 
preserved, had the two groups been in existence together in pre- 
Silurian times. 

The Devonian period, according to Chapman (16), presents 
but a single record of Foraminifera, viz. those discovered by 
Terquem (13) at Paffrath in the Eiffel. Chapman comments 
on the singular absence of Foraminifera in the Devonian seas, 
where the conditions for their existence appear to have been 
favourable. 

With the next period, however, the Carboniferous, the Fora- 
minifera first begin to justify the title of our paper as Worldr 
builders. Various genera make their appearance in such 
numbers as to form enormous deposits. In the lower Carbonif- 
erous strata the large arenaceous species known as Saccammina 
fusuliniformis (McCoy) = S. Carteri (Brady) (17) is the principal 
constituent of enormous areas of limestone in Great Britain and on 
the Continent (PI. 1, fig. 2). The upper Carboniferous limestone, 
on the other hand, is in most regions of the world largely built up 
of the shells of Fusulina, a perforate foraminifer belonging to 
the family Nummulinidae. Other genera which are largely 
concerned; in the formation of Carboniferous limestones are 
'Endothyra\i^\. 1, fig. '6) and Archaediscus, while in this period 



6 E. HERON-ALLEN AND A. EARLAND ON THE FORAMINIFERA 

occur the first records of two genera, Amphistegi?ia and Nura- 
mulites, which in later times were destined to play an important 
part in the formation of the world's crust. 

The Permian and Permo-Carboniferous rocks show a decline 
in the importance of the Foraminifera. Perhaps it would be 
more correct to say that there is a falling off in the records of 
those large and dominant types which marked the Carboniferous 
period. Foraminifera of many different genera occur in the 
Permo-Carboniferous rocks, but they are usually of compara- 
tively small size, and so do not readily form a basis for rock 
formation. But in New South Wales and Tasmania, Nubecularia, 
which is the lowest type of imperforate foraminifer, forms a 
principal constituent of some limestones (18) (PL 1, fig. 4). 

TheTrias yields no strata in which Foraminifera are the principal 
constituent. Foraminifera occur in many horizons, but do not 
constitute any large proportion of the fauna. Perhaps the 
richest deposit is that described by Chapman (19) from Wedmore 
in Somerset. 

Similarly in the Jurassic period, the Foraminifera, although 
often varied and abundant, are not responsible for any important 
proportion of the whole bulk of the formation. They are often 
confined to limited zones, in which they occur in great abundance, 
but the species are nearly all minute and completely masked as 
to external appearance by other material. The most important 
feature of this period, however, is the sudden bursting into active 
existence of numerous hyaline types, principally Lagenidae, 
hitherto more or less unknown. They occur in the clays of the 
Lias of the Continent in enormous variety, passing insensibly 
from one species into another, and the meticulous precision of 
Terquem and others who have monographed these strata has 
embarrassed the rhizopodist with a wealth of synonyms. 

Up to this period the arenaceous Foraminifera have not presented 
any great diversity of forms, although, as we have seen, certain 
genera (Saccammina, Endothyra, etc.), have played an important 
part in building up strata. But Haeusler (20) (21) has de- 
scribed a most interesting series of arenaceous types from a 
sandy marl of Jurassic (Oxfordian) age in the Canton of Aargau 
(Switzerland), which includes many genera now known to us 
only from deep water. It is altogether one of the most pro- 
nounced and characteristic rhizopodal faunas recorded in the 



IN THEIR ROLE AS WORLD-BUILDERS. 7 

fossil condition. The occurrence of this rich series of genera, 
some of which appear to be confined to this formation while 
others are hardly known except in the recent condition, suggests 
that the arenaceous foraminifera have, with few exceptions, always 
been confined to the deep sea, and that their scanty geological 
history may be due to that fact, and to the rarity of ancient deep- 
sea deposits. 

Passing to the Cretaceous period, we find the Neocomian and 
Aptian strata comparatively devoid of recognisable foraminiferal 
remains. But it is almost certain that Foraminifera of the 
smaller types existed in enormous numbers in the seas of these 
periods, leaving their evidence behind them in the shape of the 
glauconitic casts and grains which bulk so largely in the Green- 
sands. 

The Gault of England and the Continent contains a rich and 
varied foraminiferal fauna running into several hundred species. 
But although the Rhizopoda must have swarmed in the Gault 
seas, they do not constitute any large percentage of the total 
mass of the formation, and are often confined to limited zones. 

The same remark may be applied to the numerous beds of 
chalk ranging from the Chalk Marl to the Upper Chalk. It is 
one of those popular beliefs which die so hard that chalk is made 
up entirely of the shells of the Foraminifera, and the textbooks 
and microscopical works abound with statements to that effect. 
Some of the methods suggested to students for the obtaining of 
specimens can only have originated in the fertile brains of the 
authors. The beginner is instructed to obtain a lump of chalk 
and scrub it to fragments with a toothbrush under water ; or to 
place some lumps in a bag and smash them up with a hammer, 
subsequently kneading the mass under a tap until the water runs 
away clear. It is needless to say that such methods can never 
produce anything but debris and disappointment. These methods, 
together with directions for the adequate preparation of chalk 
material for examination, have been fully discussed by Heron- 
Allen in his " Prolegomena " (23). 

There are very few zones in the Chalk which do not contain 
Foraminifera, but their number is as a rule small compared with 
the whole bulk of amorphous matter. But it is probable that 
in the Chalk sea the Foraminifera really abounded, and 
that the amorphous carbonate of lime is derived largely from 



8 E. HERON-ALLEN AND A. EARLAND ON THE FORAMINIFERA 

their comminuted and dissolved remains subsequently reprecipi- 
tated. 

Certain zones of the Chalk, notably the zones of Holaster planus 
and Micrdster, yield Foraruinifera in larger numbers, but even 
here a section of the rock will show their limited distribution^ 
The bulk of the organic remains will be found to consist of small 
spherical bodies which when cut in section show as rings (PI. 2 r 
fig. 1). These, the so-called " Spheres " of the chalk, are perhaps- 
the origin of the belief that chalk is built up of the shells of 
Foraminifera. But whatever the " Spheres " may be, we are 
convinced that they are not Foraminifera. Their nature is still 
in doubt, although they have been relegated in turn to the 
Foraminifera, the Radiolaria and the Diatomaceae. Mr. W.. 
Hill, F.G.S., of Hitchin, whose knowledge of the microscopic 
structure of chalk is unrivalled, and who has devoted many years- 
to the study of these " Spheres," has published a scheme for the 
division of the Chalk into zones, based on their occurrence and 
numbers (32), but he is still unable to explain their origin and 
nature. We suggest that they may be the chitinous tests 
Of flagellate infusoria such as are found in great numbers in the 
sea to-day, of practically identical size and shape. 

The Chalk of Maestricht is rich in Foraminifera, and may 
be regarded as the starting-point of the rich Foraminiferal 
fauna of the Tertiary period, as it contains many large genera r 
OrbiioliUs, Operculina, Orbitoides, etc.> which reached a maxi- 
mum of development and distribution in Eocene and Miocene 
times. 

Passing into Tertiary times we reach the Golden Age of the 
Foraminifera; the age in which they were to reach their 
maximum development both as regards size and abundance, and 
to leave their remains in great beds extending across whole 
continents, and often of an enormous thickness. 

These Tertiary Foraminifera are very sparingly represented 
in Great Britain. The London clay, although it contains a rich 
rhizopodal fauna in a limited zone, is on the whole absolutely 
barren, and the Thanet Sands and Woolwich and Beading beds 
have yielded few records. 

In the Bracklesham beds of Hampshire, however, we find a 
zone almost entirely composed of two or three species of Nummu- 
lites. At Selsey Bill the foreshore at low tide, on the east shore, 



IN THEIR ROLE AS WORLD-BUILDERS. 

is for a large area covered with an exposure of this zone (the- 
41 Park " beds), and one cannot walk without crushing vast 
agglomerated masses of Nummulites laevigatas, extending for 
miles and occupying broad areas between tide-marks. 

Off the extremity of Selsey Bill lies the extensive reef known 
as "The Mixon." It is exposed at low tide, and is then found 
to be a limestone principally composed of one species of fora- 
minifer, Alveolina Boscii Def ranee. Other species (notably a large 
alveoliniform Jliliolina, Nummulites, and a large Polymorphina) 
are to be found in the rock, but this is dominant (PL 2, fig. 2). 
Alveolina Boscii, which has built up enormous areas of limestone 
extending across Southern Europe to the Himalayas, is still in 
existence to-day, and is now forming similar deposits off many- 
tropical shores. The Selsey specimens the only ones to be found 
in Great Britain are indistinguishable from those to be dredged 
in shallow water to-day, off the Great Barrier Reef of Queensland 
and in many other places (24). 

At Stubbington and its neighbourhood, in Hampshire, smaller 
types of Nummulites, viz. Nummulites elegans and JV. variolaria r 
are to be found in similar abundance. 

Turning to the Continent, we find these Nummulitic and 
Alveoline limestones developed to an incredible extent. With 
interruptions here and there, they spread in a broad band across- 
Europe, Asia and Northern Africa to the Himalayas, attaining 
in many places a thickness of several thousand feet (PI. 2, fig. 3). 
The species vary with the zone and locality, but, as a rule, the- 
whole rock is built up of their more or less perfect remains, and 
undeft the microscope the very debris in the interstices of perfect 
specimens is found to consist of their comminuted remains- 
(Pl. 2, fig. 4 and PI. 3, fig. 1). 

Among the more familiar instances of Nummulitic limestone- 
may be mentioned the Pyramids of Egypt, which are built of 
limestone quarried in the neighbouring Mokattam Hills, largely 
composed of a single species of Nummulite N. Gizehensis (Ehren- 
berg). We illustrate in Plate 3, fig. 1 a section through a micro- 
spheric specimen of this Nummulite, one of a series collected for us 
by Mrs. A. M. King, F.R.M.S. The peculiarity of these remains 
struck the geographer Strabo, who accounts for their presence in 
the limestone by asserting that they were the petrified remains 
of lentils from the rations of the ancients who built the 



10 E. HERON-ALLEN AND A. EARLAND ON THE FORAMINIFERA 

Pyramids.* They are to this day known locally as " Pharaoh's 
beans." t 

Philip de la Harpe begins his Monograph on the genus (27) 
with the words, " Egypt is the classic land of the Nummulites," 
and Dr. Carpenter in his Introduction (28) passes in review the 
legends which have attached themselves to this organism, from 
Herodotus (?), Pliny (?) and Strabo to the learned Clusius, who 
refers to " the popular belief of the Transylvanians that they 
were pieces of money turned into stone by King Ladislaus, in 
order to prevent his soldiers from stopping to collect them just 
when they were putting the Tartars to flight ! " J 

Tt may be remarked that Prof. Haug has suggested (31) 
abolishing the Lyellian nomenclature of geological periods for all 
epochs later than the Cretaceous, and the redistribution of the 
strata into Nummulitic, Neogene, and Quaternary. He suggests 
that the Nummulitic, whose classification is founded solely upon 
this foraminifer alone, shall be divided into the Eo-Nummulitic, 
which will comprise the Montian, the Thanetian, and the Lon- 
donian (names which speak for themselves), the Meso-Nummu- 
litic, which will comprise the Lutetian and Ludian, and the 
Neo-Nummulitic, which includes all strata from the Lower 
Oligocene up to the dawn of the Glacial Period which com- 
mences his Quaternary. 

As a rule these two dominant types, Alveolina and Nummulites, 

* Strabo, Geographica, lib. xvii. cap. i. 34: cpaal d'airoXidudrji'a.i \el\pava 
tt?s rdv epya^ofxtvocv rpocprjs. ovk direoiKe. See the note on this passage in 
Canon Rawlinson's translation (1860). 

f In spite of the fact that Herodotus (who has been credited with 
Strabo's observation on the Nummulites) expressly states (Euterpe, IT. 37) 
that the Egyptians never grew or ate beans in any form. 

X Clusius (i.e. Charles de l'Ecluse, 1526-1609), in Caroli Clusii et aliorum 
vpistolae, Paris (Epistola xxxvii.), thus records the matter : " Intellexi item 
genus quoddam lapillorum planorum et quasi circino in orbem ductorum 
inveniri in montibus qui Pannoniam a Daciasive Transilvania disterminant, 
quorum alii auri, alii argenti colorem referunt et characteribus insigniti 
videntur sed incognitis. Ferunt Ladislaum regem quum Tartaros praeda et 
spoliis onustos persequeretur atque metueret, ne militum suorum avaritia 
et ignavia, qui thesauris per viam stratis ab hostibus inhaerebant, victoria 
illi e manibus eriperetur, a Deo petiisse ut nummi illi et pecunia ab hosti- 
bus in via relicta in lapides mutarentur, quo militem sic delusum alacriorem 
haberet in persequendo hoste." A passage contemporary with, if it should 
not precede, Mr. C. D. Sherborn's earliest reference to Conrad Gesner 
(1566). 



IN THEIR ROLE AS WORLD-BUILDERS. 11 

do not exist together, but the transition from one dominant to 
the other is often quite sharp. We show a section from Sherani, 
on the N.W. frontier of India, illustrating the junction of the 
two beds. Within a thickness of two inches the rock turns from 
a Nummulitic to an Alveoline limestone (PI. 3, fig. 2). What 
possible explanation can there be for such a radical and cata- 
clysmic change, necessitating the practical extinction of one 
dominant, and the sudden rise to prominence of another, widely 
different, type? It cannot be a case of evolution, as the two 
species represent entirely different types of structure. 

With the passing of the Eocene period the Foraminifera lose 
their all-important position as rock-builders. Through Oligocene 
and Miocene times they continued to flourish, and to form 
deposits largely or entirely built up of their remains. The genus 
-Nummulites dies out, dies so completely that at the present day 
it is represented by only a single small species of rare occurrence 
in tropical seas. Alveolina persists, but no longer as a dominant. 
Orbitoides, a highly specialised type which had made its first 
appearance in the Chalk of Maestricht, attains sudden abundance 
and forms great beds of Orbitoidal limestone in all the Con- 
tinents, only to die out absolutely in the Miocene (PI. 3, fig. 3). 
But the Miocene and later Tertiary deposits, though often 
presenting an abundant and extremely varied foraminiferal 
fauna, no longer owe their existence to the occurrence of one or 
iew species in enormous numbers, except in those comparatively 
few deep-sea deposits which have been raised to the surface 
in the West Indies, New Guinea and the Pacific, and which 
are similar in structure and often in species to the deposits 
which are being found in the deep sea to-day (25) (26) (PI. 3, 

&s - i] - . .... 

Perhaps the conditions under which foraminiferal life exists 
to-day may help to explain the change. We have now no seas 
-swarming with Nummulites and Alveolina, to the practical 
exclusion of other species Here and there about the world the 
shallow-water Foraminifera are to be found in such .profusion 
that, given favourable means of preservation, we should have in 
time a true foraminiferal limestone. From the shallow waters of 
the West Indian seas we have received dredgings almost entirely 
composed of the genera Orbiculina and Miliolina. In the shallow 
lagoons of the Pacific Tinoporus baculatus, Alveolina Boscii and 



12 E. HERON-ALLEN AND A. EARLAND ON THE FORAMINIFERA 

Orbitolites complanata still form banks which impede navigation. 
But speaking generally, the activity of the Foraminifera to-day 
is displayed in another sphere. In the surface waters of the 
great oceans the few genera which are found in the pelagic- 
condition swarm in countless numbers, and their dead shells 
falling constantly to the sea floor, are there building up layers of 
Globigerina ooze which, if solidified and raised to the surface,, 
would be visible as areas of foraminiferal limestone exceeding 
even the Nummulitic limestones in extent. 

Murray and Renard estimate the area of sea bottom over 
which Globigerina ooze is at present in process of formation at 
over 49 1 million square miles. Of its depth we can, of course,, 
form no idea, but as the great oceans are practically permanent,, 
it must be very great, because we know from deep-sea deposits 
which have been elevated into land surfaces in Malta, Barbados,. 
Trinidad and Australasia, that similar deposits have been forming 
in the deep sea ever since at least Miocene times. 

Prof. Agassiz has observed (29) : "No lithological distinction 
of any value has been established between the chalk proper and 
the calcareous mud of the Atlantic," and it has been reasonably 
postulated by Prof. Jukes-Brown (30), after a careful analysis 
of calcareous oozes, that the chalk was deposited in a sea of less 
than 500 fathoms, though doubtless at a considerable distance 
from land. The time occupied in the deposit of the English 
chalk, arguing by the rate at which the Atlantic ooze is 
formed, which is one foot in a century, must have been 
150,000 years. 

We cannot but feel that this paper has already overpassed the 
reasonable limits of such a communication, but our difficulty has 
been mainly one of selection. The matter is one whose ramifi- 
cations are almost infinite. A systematic study of the dynamics 
of the subject remains yet to be completed, though significant 
beginnings have been made by Prof. Hull and by Prof. Jukes- 
Brown. A careful consideration of the factors which have led 
to the deposition of certain forms of Foraminifera and other 
microzoa in an orderly sequence, dependent for the most part 
upon current action and specific gravity, must lead us to an 
understanding of the forces which have accounted for the 
Building of the World in the form in which we know it. And 
it is by the study* of such factors, as revealed by their results, 



IN THEIR RuLE AS WORLD-BUILDERS. 13 

that geologists have been able to reconstruct the geographical 
features of ages inconceivably remote. 

Bibliography. 

1. Dawson, J. W. On the Structure of Certain Organic 

Remains in the Laurentian Limestones of Canada. Quart. 
Journ. Geol. Soc, 1865, p. 51, pi. vi., vii. 

2. Carpenter, W. B. Additional Note on the Structure and 

Affinities of Eozoon Canadense. Quart. Journ. Geol. Soc, 
1865, p. 59, pi. viii., ix. 

3. Ibid. On the Structure, Affinities and Geological Position of 

Eozoon Canadense. Intellectual Observer, No. XI., p. 278. 
2 plates. 

4. Cayeux, L. Sur la Presence de Restes de Foraminiferes dans 

les Terrains precambriens de Bretagne. Ann. Soc. Geol. 
Xord., 1894, vol. xxii., pp. 116-19. 

5. Ehrexberg, C. G. Ueber andere massenhafte mikroskopische 

Lebensformen der altesten silurischen Grauwacken-Thone 
bei Petersburg. Sitzungs. phys.-math. Kl. Monatsb. Ak. 
Wiss., Berlin, 1858, p. 324, pi. i. 

6. Matthew, W. D. On Phosphate Nodules from the Cambrian 

of Southern New Brunswick. Trans. New York Acad. 
Science, 1893, vol. xii., pp. 108-20 and pi. i.-iv. 

7. Matthew, G. F. The Protolenus Fauna. Trans. New York 

Acad. Science, 1895, vol. xiv., pp. 109-11, pi. i. 
S. De Lapparent, A. Traite de Geologie, 4th ed., 1900, Paris, 
p. 790. 

9. Chapman, F. Foraminifera from an Upper Cambrian 

Horizon in the Malverns. Quart. Journ. Geol. Soc, 1900, 
pp. 257-63, pi. xv. 

10. Keeping, W. On some remains of Plants, Foraminifera and 

Annelida in the Silurian Rocks of Central Wales. Geo- 
logical Magazine, 1882 ; Dec. II., vol ix., p. 490. 

11. Blake, J. F. Lower Silurian Foraminifera. Geological 

Magazine, 1876, N.S. (Dec. II.), vol. iii., p. 134. 

12. Brady, H. B. Note on some Silurian Lagenae. Geological 

Magazine, 1888, pp. 481-84. 

13. Terquem, O. Observations sur quelques fossiles des 

Epoques Primaires. Bull. Soc. Geol. France, Ser. 3 (1880), 
vol. viii., pp. 414-18, and pi. xi. 



14 E. HERON-ALLEN AND A. EARLAND ON THE FORAMINIFERA 

14. Chapman, F. On some Fossils of Wenlock Age from Mulde r 

near Klinteberg, Gotland. Ann. Mag. Nat. Hist., 1901 r 
pp. 141-60, pi. iii. 

15. Vine, G. R. Notes on the Annelida tubicola of the Wenlock 

Shales from the washings of Mr. G. Maw, F.G.S. Quart, 
Journ. Geol. Soc, vol. 32 (1882), p. 390. See also 
F. Chapman, Ann. Mag. Nat. Hist., 1895, Ser. VI.,. 
vol. xvi., p. 311. 

16. Chapman, F. The Foraminifera. London, 1902, p. 255. 

17. Ibid. Note on the specific name of the Saccammina of the 

Carboniferous Limestone. Ann. Mag. Nat. Hist., 1898, 
Ser. 7, vol i., pp. 216-18. 

18. Chapman, F., and Howchin, W. A monograph of the 

Foraminifera of the Permo-Carboniferous Limestones of 
New South Wales. Mem. Geol. Survey, New South Wales, 
1905. Palaeontology, No. 14, p. 5. 

19. Chapman, F. On some Foraminifera of Rhaetic Age from 

Wedmore, in Somerset. Ann. Mag. Nat. Hist., 1895 r 
Ser. 6, vol. xvi., pp. 305-29, 2 plates. 

20. Haeusler, P. Die Astrorhiziden und Lituoliden der 

Bimammatus-zone. Neues Jahrb. filr Min., 1883, vol. i. r 
pp. 55-61, pi. iii., iv. 

21. Ibid. Monographie der Foraminiferen der Transversarius- 

Zone. Abhandl. Schiveiz. Paldont. Gesellsch., 1891,, 
vol. xvii., pp. 1-135, 15 plates. 

22. Mobius, K. Der Bau der Eozoon Canadense nach einigen 

Untersuchungen vergleichen mit dem Bau der Foramini- 
feren. Cassel, 1878. 

23. Heron-Allen, E. Prolegomena towards the study of the 

Chalk Foraminifera. London, 1894, pp. 10-14. 

24. Heron-Allen, E., and Earland, A. The Recent and Fossil 

Foraminifera of the Shore-sands at Selsey Bill, Sussex. 
Journ. R. Micr. Soc, 1908, p. 529; 1909, pp. 306, 422 r 
677 ; 1910, pp. 401, 693 ; 1911, pp. 298, 436. 

25. Schubert, P. Die fossilen Foraminiferen der Bismarck- 

archipels und einiger angrenzender Inseln. K. K. Geo- 
logischen lieichsanstalt, vol. xx. Part 4. Vienna, 1911. 

26. Jukes-Brown, A. J., and Harrison, J. B. The Geology of 

Barbados. Part II. The Oceanic Deposits. Quart. 
Joarn. Geol. Soc, 1892, vol 48, p. 170. 



IN THEIR ROLE AS WORLD-BUILDERS. 15 

27. La Harpe, P. de. Monographie der in Aegypten und der 

libyschen Wiiste vorkommenden Nummuliten. Palaeonto- 
graphica, vol. xxx. 1883 (3 Folge, Bd. 36), p. 155. 

28. Carpenter, W. B., Parker, W. K., Jones, T. B. Intro- 

duction to the study of the Foraminifera. London (Ray 
Soc), 1852, p. 262. 

29. Agassiz, A. Three Cruises of the Blake. London, 1888,. 

vol. i., p. 150. 

30. Jukes-Brown, A. J. Handbook of Physical Geology. 

London, 1884, p. 130. 

31. Haug, E. Traitede Geologic II. Les Periodes Geologiques. 

Fascicule 3. Paris, 1911. 

32. Jukes-Brown, A. J. The Cretaceous Bocks of Britain, with 

contributions by W. Hill. London, Geological Survey, 
volii., 1903, vol. iii., 1904. 



Description of Plates 1 3. 

With the exception of PI. 1, fig. 1, PI. 3, fig. 4, the figures are 
from original sources. 

Plate 1. 

Fig. 1. Spirillina Limestone. Upper Cambrian, Malvern (after 
Chapman, Q.J.G.S., vol. lvi., 1900, Plate 15). 

,, 2. Saccammina Limestone. Carboniferous. Pathhead, Had- 
dington, N.B. 

,, 3. Endothyra Limestone. Carboniferous. Indiana. 

4. Nubecularia Limestone. Permo- carboniferous. Polkolbin, 
Maitland, N. S. Wales. 



Plate 2. 

Fig. 1. Middle Chalk. Zone of Rhynchonella Cuvieri. Hitchin. 
,, 2. Alveolina Limestone. Eocene. Mixon Bock, Selsey. 
,, 3. Alveolina Limestone. Eocene. Bunnu, N. W. Frontier 

India. 
, 4. Kummulitic Limestone. Eocene. Gizehj Egypt. 



16 E. HERON-ALLEN AND A. EARLAND ON THE FORAMINIFERA. 

Plate 3. 

Fig. 1. Nummulites Gizehensis (Ehrenberg), microspheric speci- 
men. Horizontal section, through primordial chamber. 
2. Alveolina and Nummulitic Limestone. Eocene. Shiranni, 
N. W. Frontier, India, showing the junction of the 
two beds. 

3. Orbitoidal Limestone. Miocene. Japan. 

4. Globigerina Limestone. Miocene. Bismarck Archipelago, 
Pacific (after Schubert, loc. cit., Plate 5, fig. 4). 






Jourii. Quekett MicroscopicabClub, Ser. 2, Vol. XIL, No. 72, April 1913. 



Journ. Q.M.C. 



Ser. 2, Vol. XII., PI. 1 







3 4 

Fo RAM IN I FERAL LIMESTONES. 



Journ. Q.M.C. 



Ser. 2, Vol. XII., PI. 2. 







FoRAMINIFERAL LIMESTONES. 



Journ. Q.M.C. 



Ser. 2, Vol. XIL, PL 3. 







3 4 

FORAMINIFERAL LIMESTONES. 



17 




NOTES ON SOME OF THE DISCOID DIATOMS. 

By W. M. Bale, F.R.M.S. 



(Contributed by Prof. A. Bendy, January 2Sth, 1913.) 

In the following notes, written for the most part several years 
since, I have attempted, in somewhat desultory fashion, a survey 
of some of the principal characters which have been utilised in 
the discrimination of species in three or four of the best-known 
genera of discoid diatoms. Some of the conclusions at which I 
have arrived as to the inadequacy of many of these distinctions 
have, I am aware, been reached by previous observers, more 
especially in the genus Coscinodiscus ; but in such cases the 
special instances now brought forward may perhaps be service- 
able in reinforcing those conclusions. In other cases, particularly 
in the genus Actinoptychus, my observations tend to prove that 
characters accepted as specific even by recent authors are de- 
monstrably unreliable. I have not pursued my investigations 
more fully, as I have found the subject too difficult, owing to the 
impossibility of procuring much of the literature, and to my total 
isolation from other observers. I trust, however, that these notes 
may not be without interest for students of the Diatomaceae, 
and that the suggestions therein may be of some value to those 
who occupy themselves with their classification. 

Coscinodiscus. Notwithstanding all that has been done to- 
wards the elucidation of this unwieldy genus, it still remains the 
most difficult as it is the most extensive of the whole order. 
This follows naturally from the general similarity of form, and 
the absence in most cases of any specialised areas or conspicuous 
appendages such as serve to distinguish the species in Actin- 
cptychus, A uliscus, etc. Many forms which have been described as 

Journ. Q. M. C, Series II. No. 72. 2 



18 W. M. BALE ON SOME OF THE DISCOID DIATOMS. 

distinct differ only in having the markings a little smaller or 
larger, while others are characterised by trifling distinctions of 
detail which, on examination of an extended series of specimens, 
are found to break down utterly. On the other hand it will be 
seen that, in many instances, details which might be helpful in 
the discrimination of species have been generally overlooked. 

The first serious attempt to grapple with the difficulties 
involved in the classification of the genus was that of Grunow,. 
in his work on the Diatoms of Franz-Josef Land, a perusal of 
which leads one to regret that this acute observer did not carry 
out a more comprehensive survey of the whole genus. Rattray's 
Revision, though giving evidence of a vast amount of painstaking 
research, is far from final in regard to the species admitted, 
many of which are characterised by features obviously not of 
specific sometimes not even of varietal value. Moreover, in 
working over slides from well-known deposits, one finds many 
forms which it is impossible to place under any of the species 
described, though it is most unlikely that Rattray could have 
failed to observe them. The impression is produced that many 
of the descriptions have been framed on particular specimens,, 
without any allowance for the range of variation usually present. 
The "key" is minimised in value owing to the use in many of 
the sections of characters which are quite inconstant, or which 
may characterise the type but not the varieties, while the attempt 
to include all the sections in one key has added much to the 
difficulty of the undertaking, and has involved mistakes which 
render it in some cases quite unreliable. (As an example, let 
the observer take a typical valve of C. asteromphalus and attempt- 
to trace it through the key, and he will fail to find it. But it 
appears under Section 116, and, if followed backwards, it will 
be referred to Section 111, where the description is, "Markings 
rounded, granular ; interspaces hyaline, unequal, rows radial," 
which obviously cannot apply to the species at all.) 

Nevertheless Rattray's work undoubtedly represents a great 
advance in its suppression of a large number of pseudo-species, 
though one cannot but regret that the process has not been 
carried further. 

Mr. Cox, going to the opposite extreme, would reduce all the 
multitudinous forms of Coscinodiscus to seven species, Actinocyclus 
Ehrenbergii being included as one of them. Some diatomists 



W. M. BALE ON SOME OF THE DISCOID DIATOMS. 19 

have expressed approval of this proposal, but none have adopted 
it, nor are any likely to do so. 

In surveying the various characters by which species may be 
defined, the outline will naturally be the first to be considered. 
This in the Coscinodisci, however, is of little assistance, as, except 
in a few aberrant species, the circular form prevails. Passing to 
the surface contour, we have a character which has been utilised 
by Grunow, Rattray, and others, but by no means so fully as 
might be. Thus neither of these observers, in differentiating 
C. asteromphalus from C. centralis, refers to the fact that the 
former has usually the centre depressed, while the latter is 
convex throughout. In several cases the absence of information 
on this point in Rattray's descriptions just renders the diagnosis 
doubtful. And this is the more important from the fact that 
even a good figure does not always bring out this special point. 
At the same time it may be observed that it is not rare for 
individuals of a given species to depart from the normal character 
in regard to surface contour, and further, that in particular 
localities this variation may prevail. This refers especially to a 
tendency for the surface to be more depressed than is normally 
the case, and does not apply to C oscinodiscus only. Thus in some 
of the Oamaru deposits we find that Aulacodiscus margaritaceus, 
A. amoenus and the large forms of the Triceratium favus group 
are all characterised by the unusually depressed surface of the 
valves. 

It may be noted, further, that it is not safe to describe the 
surface contour of a species without examining both valves. 
Rattray describes C. superbus as convex, but in reality one valve 
is convex, while the other has the centre depressed. Several 
species, such as C. tumidus, have the surface concentrically undu- 
lated, while in a series of forms, described by Grunow as Pseudo- 
Stephanodiscus, there is an asymmetrical inflation of the surface. 
The inflations and depressions in C. excavatus are also familiar 
examples of specialised areas. 

Variations of the radial symmetry, other than those men- 
tioned, are rare. A notable instance is that of C. cocconeiformis, 
which has the markings bilaterally arranged. 

In the great majority of cases the form, size and arrangement 
of the cellules or puncta which cover the surface are the prin- 
cipal or sole ground relied upon for specific distinction, many 



20 W. M. BALE ON SOME OF THE DISCOID DIATOMS. 

so-called species being differentiated solely by slight variations in 
the size of the areolation, or by its increasing or decreasing 
in size towards the margin. All such species, unless other and 
weightier differences can be found, should be swept aside as 
spurious. The same remark applies to the presence or absence 
of a central area, of a central rosette of larger areolae, of 
bright points at the origin of the shorter radial series, of parts 
of the surface where the polygonal areolation is replaced by 
separate circular cellules, and of fine punctate secondary markings. 
Any of these characters may, of course, be constantly associated 
with a particular species; but, in many species at any rate, 
examination of a sufficient series readily shows that they may be 
indifferently present or not. Indeed, within the limits of the 
single species C. asteromphalus a range of forms may be found 
some or other of which exhibit every one of the characters just 
mentioned, while others show none of them. 

In some respects the size of the valve (i.e. with reference to 
the average of the species) is a determining factor in the 
arrangement of the markings. Thus in such forms of C. radiatus 
as are usually considered typical there are commonly three or 
four slightly larger cellules in the centre, and the rest are in 
distinctly radial series. In smaller valves the central cellules 
are no longer than the rest, and in the smallest forms the radial 
disposition of the cellules is totally lost. A still more striking 
instance is found in one of the robust forms of C. asteromphalus, 
common in some of the North American deposits. The largest 
valves have a conspicuous central rosette of large cellules, and 
outside these the areolae are much smaller, gradually increasing 
in size, however, to the mid-radius. With a diminution in the 
size of the valve comes a modification in the direction of levelling 
down the differences in size of the areolation the rosette-cells 
become smaller, and those next to them larger in proportion. 
One stage in this series is the C. biangulatus of Schmidt, which 
is only a normal form of this group, and by no means of specific 
or even varietal value. In the smallest forms of the series all 
trace of the rosette is wanting, the areolae are fairly uniform in 
size throughout, and the centre of the valve is not depressed as 
in larger specimens, but convex or very slightly flattened, while 
in many valves the cellules are separate and circular on part of 
the surface, as in C. perforatus and C. apiculatus. Similarly the 



-I 



W. M. BALE ON SOME OF THE DISCOID DIATOMS. 21 

C. crassus, so abundant in the Sendai deposit, simply consists of 
the smaller valves of the equally abundant G. borealis, to which 
it bears the same relationship that C. biangulatus does to 
C. asteromphalus. 

In C. marginatus the small valves, with uniform and non- 
radial areolation, are considered typical, but, as in the above- 
mentioned species, we find that valves of maximum size have the 
areolation distinctly radial, with the areolae increasing in size 
from the central rosette towards the margin. 

In other species similar conditions occur, indicating that the 
reduction of the differences in size of the areolae is the regular 
concomitant of the reduction in size of the valves, and showing 
how little such variations are to be relied on as specific 
distinctions. 

The presence of a central area may be of specific value in 
some instances, but in many species it is quite worthless even as 
a varietal character. Sometimes its disappearance is due to the 
cellules surrounding it becoming enlarged at its expense. Thus 
in C. perforatus and C. apiculatus normal valves (if indeed wo 
are right in considering as normal those valves with separate 
round markings, which I greatly doubt) have a blank central 
space, and the cellules surrounding it are in no way different 
from the rest, but when, by the enlarging of the cellules- 
generally at the expense of the intervening substance, the 
structure becomes areolate, the most central cellules often 
enlarge inwards till they obliterate the area, and thus form a 
rosette, as in C. Oculus Iridis, etc. 

Far too much importance has been attached to the area in 
Rattray's monograph, especially in the key. 

The central rosette is one of the most variable of characters. 
In some cases, as already mentioned, it is conspicuous in the 
largest valves, dwindling and finally vanishing in the smaller 
ones ; in others, just alluded to, it results from the obliteration, 
entire or partial, of the central area. In some no doubt it 
may be regarded as a fairly constant specific character. 

The tendency in some species for the polygonal areolation to 
be replaced on a portion of the valve by isolated circular cellules 
may be briefly referred to. C. perforatus and C. apiculatus are 
familiar cases in which this modification occurs, either over the 
whole surface of the valve, or on more or less of one side, while 



22 W. M. BALE ON .SOME OF THE DISCOID DIATOMS. 

in C. gigas, G. diorama, and a few others, it is the central part 
of the valve which is so modified. Though in C. apiculatus and 
C. perforat us it is universally recognised that this peculiarity is 
not of specific importance, the loose disposition of the markings 
in the central part of such species as C. diorama has been made 
use of to characterise the species, but in some cases at least 
unwarrantably. In a species found in Port Phillip the larger 
valves have the markings as in G. diorama, while the smaller 
ones are areolate throughout. When the modification in question 
occurs in the central part of a valve it is usually associated with 
a thinner condition of the silex, but this does not appear to be 
the case in such species as G. perforatus and G. apiculatus. 

In rare cases the loosely disposed and rounded markings occur 
on an annular area, concentric with the margin, and an interest- 
ing example of this is found in the large, robust form of G. Oculus 
Iridis found in the Mors deposit. It is a variable form as regards 
the surface contour, but commonly in large valves the centre and 
the sub-marginal zone are about equally elevated, and the inter- 
vening broad annular area is slightly depressed. A varietal 
form differs in having this depression much deeper, and, on the 
outer side, very abrupt, while in a third form the annular 
depression is very deep and narrow, and on the bottom of the 
depression the cellules are rounded and separate (a condition to 
which there is sometimes a tendency in the second form). This 
last variety was described by Grunow in his work on the diatoms 
of Franz-Josef Land as a new species, under the name of 
G. annidatus, notwithstanding which it was figured later on 
PI. 184 of Schmidt's Atlas under the name of Craspedodiscus 
Molleri. 

I have also seen a form of G. excavatus, very near to Grunow' s 
var. semilunaris, in which there is a complete annular depression, 
with round markings, not far from the centre. 

The circular areas of the varieties just mentioned, as well as 
the inflations of ordinary forms of G. excavatus, are all instances 
of abrupt bulging in (or out) of the substance of the valve, and 
in all of them the portion which is subject to this bulging 
appears thinner than the rest of the valve, while the markings 
are fainter, as well as being rounded and loosely disposed. 

The occurrence of " bright points " at the origin of the shorter 
radial series of cellules has been commonly regarded as a valid 



W. M. BALE ON SOME OF THE DISCOID DIATOMS. 23 

specific character. In some instances these " bright points " are 
merely the optical expression of a local thickening of the silex ; 
more generally, however, they are true cellules, differing from the 
rest in their minute size. They are conspicuous in C. perforatus, 
and they form the principal ground of distinction between that 
species and C. apiculatus. But in examining a large series of 
. perforatus var. ceilulosa I find them by no means so constant 
as to justify the importance attached to them. While in some 
valves they appear at the origin of all, or nearly all, the shorter 
rows of areolae, in others they are much sparser, and in a few 
cases I failed to detect more than four or five on the whole valve. 
In such cases, and when, as often happens, the central area is 
obsolete, it is a critical matter indeed to distinguish the valve 
from C. radiatus, and in passing I may note that the " C. radiatus" 
of my Holler's Typen-Platte is just one of these valves of 
C. perforatus var. ceilulosa, with all its bright points complete. 
C. obscurus may be mentioned as another species in which the 
bright points, usually present, may be either totally absent or 
reduced to a very small number. On the other hand the points 
often occur in species which are normally without them. I have 
met with instances of this kind in C. aster omphalus, on a narrow 
unilateral area where the cellules are separate and rounded. In 
a slide from Cambridge, Barbados, there are numerous valves of 
C. excavatus, most of which display these minute cellules, and in 
some valves not only at the origin of the radial series, but 
profusely interspersed among the large areolae all over the 
surface, even in places other than the angles of the areolae. And 
I have a curious valve of Endyctia oceanica, in which these 
minute cellules form the principal part of the areolation, the 
ordinary large cells only existing in scattered groups of four or 
five, surrounded on all sides by the network of small ones. 

I have referred already to the small importance to be attached 
to mere differences in the size of the areolation, but I would 
further remark that it must by no means be assumed that only 
small differences are to be disregarded. Valves of C. concinnus 
may have only four cellules in 0*01 mm., while others may have 
as many as twelve, though the valve may be much larger. And 
I have seen a frustule of C. excentricus in which one valve was 
twice as finely marked as the other. Such instances show forcibly 
the futility of distinctions founded on the size of the areolation. 



24 W. M. BALE ON SOME OF THE DISCOID DIATOMS. 



\ 



The structure of the valve-border is a feature which has not 
always received sufficient attention from observers, who have 
overlooked peculiarities which might be of service in classification. 
This refers to the general character of the border, and more 
particularly to the minute appendages which it frequently bears. 
The apiculi which form a circlet at the margin of many species 
are familiar to all observers, more especially those which in some 
of the Fasciculati and Cestodiscoidales attain a prominence which 
could not fail to attract attention. But those which are 
asymmetrical, and of which only one or two appear on each valve, 
have hitherto singularly escaped notice, except in a very few 
instances, where they are more conspicuous than usual. For 
example, in the robust form of C. lineatus, described as C. leptopus, 
a single larger apiculus, farther in than the rest, is quoted by 
Rattray as distinguishing C. leptopus from its allies. Y~et in 
fact it is not peculiar to this form, a similar apiculus, but more 
delicate, being easily discoverable in other and more nearly 
typical forms of C. lineatus. Further, it is equally a feature of 
C. excentricus, and I find it commonly present, though apparently 
hitherto unnoticed, in forms of that species from such different 
localities as Port Phillip, Cuxhaven, Santa Monica, and Peru and 
Bolivia guanos. (There is, of course, no justification for the line 
of demarcation drawn by Battray between the respective groups 
of the Lineati and the Excentrici. The two type species are con- 
nected by intermediate forms, and the same remark applies to 
C. excentricus and C. subtilis.) 

Among the Badiati the tendency is towards the production of 
two apiculi, which occupy positions about one-third or one-fourth 
of the circumference apart. They are found in many species,, 
though strangely enough I can find no mention of them by any 
observer except in the cases of G. concinnus and C. centralis, in 
both of which forms they are very conspicuous. Battray says 
that C. centralis is distinguished from C. asteromphalus by these 
apiculi, and cannot be united with it in the same species, as pro- 
posed by Grunow. An unfortunate dictum, since all, or nearly 
all, of the numerous varieties of C. asteromphalus agree precisely 
with C. centralis in this respect, while such apiculi, but more 
rudimentary and indefinite, are found in a wide range of forms 
comprised under C. marginatus, C. perforates, C. apiculatus r 
C. borealis and others. Their minute size and indefinite form 



W. M. BALE ON SOME OF THE DISCOID DIATOMS. 25- 

cause them to be easily overlooked against the coarsely marked 
background of the valve-areolation, but in C. concinnus and 
G. centralis they are more conspicuous, owing largely to the more 
delicate and transparent condition of the valve. 

The key to the position of these apiculi is, however, to be found 
in certain modifications of the valve-border which occur in the 
vicinity, and which indeed are often obvious when it is difficult 
or impossible to detect the apiculi themselves. These modifications 
may take the form of a thinning away of the valve-surface (C. 
marginatus), or an apparent notching of the margin (C. borealis, 
C. diorama, etc.), or a sinuation of the inner edge of the thickened 
border (G. aster omphalus) . In the last species this marginal 
structure is very conspicuous, at least in the robust valves, and it 
is shown in Schmidt's figures of C. biangulatus and one or two 
others. 

In C. perforatus and C. apiculatus (at least in the areolate 
forms) two minute notches in the extreme margin of the areo- 
lation can in most cases be seen, and by careful examination the 
apiculi may generally be found opposite them, but they appear 
no more than a slight thickening of the silex, w T hich would 
certainly never be noticed except for the marginal clue. In 
C. marginatus the coarse radial structure of the marginal zone is 
thinned away over two comparatively large areas, sometimes very 
noticeably, but the apiculi themselves are difficult to make out. 

The apiculi are most fully developed in C. centralis and C. 
aster omiAalus. They are best seen by examining the inside of 
a large valve in which the marginal part is steeply convex, so 
that the apiculi, which project into the valve a little above the 
rim, can be observed without the interference of an immediate 
background. The apiculus takes the form of a minute disc, 
attached by a central point, and bearing a sub-globular or irregular 
mass. The border in C. asteromphalus is usually widened in- 
wardly so as to form an annular projection into the cavity of 
the frustule. The extent to which this widening takes place 
varies greatly, even in the same variety ; but whatever its width, 
so long as it projects inwards at all, it is sinuated under the 
apiculi, which are always uncovered, so that the sinuations are 
deeper as the valve-border is wider. The structure would seem 
to imply the presence in the living organism of some direct 
communicating filaments between the apiculi of the two valves, 



) W. M. BALE ON SOME OF THE DISCOID DIATOMS. 

on which the inward extension of the border must never encroach. 
I have had no opportunity of proving whether this is so, or even 
o: ascertaining whether the apiculi of the two valves are opposite, 
except in a single instance a large cylindrical frustule of C. 
mirificus mounted in zonal view, and in this the apiculi are 
opposite. 

In C. gigas the apiculi are, if present, obscure, and I can find 
no marginal indications of them. C. diorama and allied forms, 
however, often classed as varieties of C. gigas, have the border 
distinctly marked with two apparent notches as in C. perforatus. 
C concinnus has distinct apiculi, and many specimens have in 
addition crescentic processes outside the valve, partly surrounding 
the point at which the apiculi originate. These valves are known 
as Eupodiscus Jonesianus Greville (E. commutatus Grunow), but 
I do not think they have any claim to rank even as a variety. 
They are abundant in slides from Ouxhaven, mixed indis- 
criminately with valves having the internal apiculi only. 

While several forms besides those which I can identify with 
the foregoing species share in the peculiarity in question, there 
are many others in which I have failed to detect it. Such are the 
thick variety of C. Oculus Iridis found in the Mors deposit, also 
C. radiatus. In more typical forms of C . Oculus Iridis, however, 
careful search has disclosed two apiculi, which are simple bacillar 
projections into the cavity of the frustule. 

Apart from these appendages the structure of the border itself 
has in many cases not received sufficient attention as a help in 
classification. Some species have distinct borders with markings 
quite different from those of the valve generally, others have the 
areolar structure continued to the extreme margin without 
interruption ; in some the edge is turned over, in others it is 
quite flat, and frequently the specific diagnosis contains no 
hint of the character of the valve in this respect ; so that of two 
valves, differing widely in this particular, it may be impossible to 
decide which of them corresponds with the specific description. 
C. concinnus and C. centralis may serve to illustrate this. Both 
are very convex, but in the former the marginal part is slightly 
flattened, the areolae diminish to a very minute size, and are 
succeeded by an extremely narrow hyaline border, thinning 
away so as to show only a smooth single contour. In a typical 
C. centralis, on the other hand, the valve curves downward to the 



W. M. BALE ON SOME OF THE DISCOID DIATOMS. 27 

extreme edge, and the areolae are of an appreciable size throughout, 
while the border is not thinned away, so that on focusing the 
margin there is visible a distinct double contour, with the walls of 
the last row of cellules showing as coarse transverse striae. 

Several species exhibit a tendency for the border to become 
wider in proportion as the valves are smaller. C. obscurus and 
V. apiculatus are instances of this. In both these species I have 
traced a series down to forms with wide borders, which are 
only to be distinguished with difficulty from C. marginatus. 
In Nottingham and other American deposits such forms of 
C apiculatus are common, and one of them figured by Schmidt 
(PI. 62, f. 11, 12) has been referred by Rattray to C. marginatus. 

In several species of the Radiati the angles of the areolae often 
tend to become thickened, so that in a certain focus there appears 
to be a bead at each angle. This feature has no specific im- 
portance, and I agree with Rattray that the presence at each 
a,ngle of a distinct spine, as occasionally found, is of no greater 
consequence. 

I have already referred to the close affinity which exists 
between the Excentrici and the Fasciculati, e.g. between C. ex- 
centricus and C. subtilis. Grunow mentioned this affinity, but 
Rattray says that it is remote. Grunow's view is undoubtedly 
correct. In a typical G. excentricus there is a central cellule, 
and surrounding it a circle, generally of seven. Each of these 
seven is the centre of an arcuate line of cellules, extending to 
the margin on either side, behind which is a succession of similar 
arcuate series, so that the whole of the cellules may be regarded 
as forming seven fascicles, crossing each other symmetrically, so 
that no division-lines exist, and for the most part each cellule 
will form part of three different fascicles. In C. subtilis and 
C. symbolophorus the number of fascicles is greater, and the 
divisions between them more abrupt, especially in the central 
part of the valve, so that the fasciculation is more manifest, but 
even in these forms the fascicles blend towards the margin in the 
same way as those of C. excentricus. I have seen a frustule of 
the latter species in which one valve was normal, while the 
other was far more finely marked, and was as distinctly 
fasciculate as C. subtilis. 

I should mention that the C. subtilis referred to is Grunow' 
typical form, which is quite different from Rattray's, though 



W. M. BALE ON SOME OF THE DISCOID DIATOMS. 

that observer quotes Grunovv as his authority. He describes 
C. subtilis as apiculate, and differentiates other species from it 
by the absence of apiculi. Yet Grunow says expressly that 
C. subtilis is non-apiculate. " Der Ausgangspunkt fiir alle diese 
Formen ist der stachellose C. subtilis (Ehr. partim), Gregory, 
Grunow " (Diat., F.-Josef Land, p. 81). This form, which is similar 
to C. symbolophorus, but without the stellate markings at the 
centre, also agrees well with Rattray's own account of Ehren- 
berg's original species. It is not common, and Yan Heurck 
figures it from guano, not finding it in European gatherings. 
But Peragallo, like Rattray, though claiming to follow Grunow's 
authority for the type, has figured and described a totally different 
form an apiculate variety. 

Actinocyclus. The excessive multiplication of specific names 
which encumbers the Coscinodisci has not been carried out to a 
corresponding extent in the much smaller group of the Actino- 
cycli (ignoring, of course, Ehrenberg's multitudinous pseudo- 
species) ; still there is no doubt that an undue regard for certain 
points of structure has led to the establishment of several species 
on insufficient grounds. Rattray's monograph admits about 
seventy species : Fome of these have no claim to recognition, but, 
on the other hand, I find that about fifteen out of thirty-four 
species or varieties which I possess cannot be identified with any 
of Rattray's descriptions. He has adopted in this monograph 
the plan of furnishing extremely long and minutely detailed 
descriptions, a method which renders identification more certain 
when one is dealing with the precise form described, but does 
not allow for the variations which constantly present themselves 
even in a single gathering. In fact, as I have remarked in 
reference to Coscinocliscus, many of these are not descriptions 
of species, but of individual diatoms. Mr. Rattray uses five 
places of decimals to express the fraction of a millimetre which 
corresponds to the diameter of a pseudo-nodule ! Of what 
possible use can such measurements be when applied to structures 
so notoriously variable ? 

Before discussing the range of variation in the genus, and 
as I shall refer repeatedly to the commonest species A. Ehren- 
bergii I must premise that I use that name in the sense in 
which it is used by Ralfs himself, and by Yan Heurck, Grunow, 
Peragallo, and, so far as I know, by all other observers except 



W. M. BALE ON SOME OF THE DISCOID DIATOMS. 29 

Rattray, who has unaccountably assigned the name to an entirely 
different form, while describing the true A. Ehrenbergii as 
A. moniliformis Ralfs. A. Ehrenbergii was described by Ralfs 
from his own knowledge, while A. moniliformis was merely a 
name given by him to certain forms from Oran and Virginia, 
which he had not seen, but which he judged from Ehrenberg's 
tigures to be distinct, the distinction consisting in the division 
of A. Ehrenbergii into compartments by double lines, while 
A. moniliformis was divided by single ones. There is really no 
difference, except such as depends on the size of the valves and 
the number of the fasciculi. In small valves, containing few 
fascicles, the interfasciculate rays form a wide angle with the 
other series, and are therefore very marked ; and these are the 
" single series of dots " referred to by Ralfs. In large valves 
the fascicles are numerous and narrow, so the interfasciculate 
rays form a small angle with the other series, which, stopping 
short at various points, leave a double row of subulate blank 
spaces along the sides of each primary or interfasciculate ray, 
and 'these subulate areas constitute the "double lines" of Ralfs. 
That the small valves from Oran and Virginia, and the large 
ones from Cuxhaven, etc., are one and the same species is fully 
recognised, however, by Rattray, but he names them A. monili- 
formis. To any one who reads carefully Ralfs' account of 
A. Ehrenbergii there can be no possible doubt as to the identity 
of the species. It was established specially to include the 
many-rayed forms described by Ehrenberg, which mostly occur 
at Cuxhaven ; Ralfs also states that it is " very fine in Ichaboe 
guano," and that most of the forms can be obtained therein ; 
and further, that it is " common, both recent and fossil." One 
species, and only one, answers perfectly to this description, 
namely, that which Rattray calls A. moniliformis, but which, 
in its larger forms, at least, has been recognised by observers 
generally as A. Ehrenbergii. Rattray might have been justified 
in preferring the name of A. moniliformis on the ground of 
priority, but he has failed to perceive that the forms which he 
has placed under it are no other than the A. Ehrenbergii of 
authors, and has inexplicably assigned the name A. Ehrenbergii 
to a species (or variety) differing entirely from that described 
by Ralfs. It is not found at Cuxhaven, nor, so far as is known, 
in Europe at all ; it is far from being common, either recent 



30 W. M. BALE ON SOME OF THE DISCOID DIATOMS. 

or fossil, and it is not found in Ichaboe guano. It is dis- 
tinguished from the true A. Ehrenbergii by its concentrically 
undulated valves, by its strong iridescence, and by its sharply 
defined zones of colour under low powers. Its granules are 
also more closely and regularly arranged, forming over the 
greater part of the valve a very regular areolation. To 
distinguish it from the true A. Ehrenbergii I propose for it 
the specific name of A. rex. I have only found it in the 
deposits of Nottingham, Curfield, Atlantic City, and Lyons 
Creek. Rattray's localities are necessarily unreliable, so far 
as they are given on the authority of other observers, of whom 
some at least (Ralfs, for example) were referring to the true 
A. Ehrenbergii, and not this form at all. 

Rattray's description of this species, however, requires amend- 
ment, especially as regards the contour of the valve. He says- 
that large valves have the centre depressed, and two concentric 
elevated zones between the centre and the border, while small 
valves have the centre depressed, and are convex between it and 
the border. This is correct so far as some of the valves are 
concerned, but in others the surface elevations and depressions 
are in the opposite order. Thus in large valves the centre is 
convex, and there is one elevated zone between it and the border^ 
Evidently the frustule is concentrically undulated as a whole, 
the depressions of one valve corresponding to the elevations of 
the other. So in the case of the small valves with depressed 
centre, others, evidently their counterparts, have the centre 
convex. Some of the valves in my slides are 0*20 mm. in diameter, 
Rattray's maximum being 0*17. 

The largest European species is, according to Rattray, A.Ralfsii r 
of which I have not seen specimens agreeing entirely with 
Peragallo's description of the type ; but among the forms of 
A. Ehrenbergii abundant in slides from Cuxhaven and Ichaboe 
guano are many which agree with that description in the 
arrangement of the fasciculi and subulate areas, though not in 
the brilliant appearance, the very large pseudo-nodule, nor the 
concentric arrangement of the granules. One has only to read 
the descriptions of Ralfs, Yan Heurck, Rattray and Peragallo 
to see that no two of these observers agree as to the respective 
characters of A. Ralfsii and A. Ehrenbergii, which is nob sur- 
prising if, as Peragallo states, every intermediate gradation 



W. M. BALE ON SOME OF THE DISCOID DIATOMS. 31 

exists between the two types. This agrees with the views 
expressed by Grunow, Lagerstedt, and others ; it would seem, 
therefore, that Peragallo is justified in treating A. Ehrenbergii 
as at most a variety of A. Ralfsii. 

Most species of A.ctinocyclus have the markings arranged on 
the same general plan as A. Ehrenbergii. The surface of the 
valve is divided into cuneate areas by a number of moniliform 
series of granules (the interfasciculate rays), which radiate from 
the centre, or near it, to the marginal zone. Each cuneate area 
contains a fascicle of similar moniliform series, but only the 
central one is strictly radial, and all the others are parallel 
with it ; and as they all stop short of the interfasciculate rays 
they are necessarily shorter as they approach these rays. The 
great difference in the aspect of the valves dependent on the 
small or large number of fascicles has already been mentioned. 
In the largest valves, where they are most numerous, they are 
so narrow that they consist of very few series of granules, and 
the angles which they form with the interfasciculate rays are so- 
small that at first sight it might appear that all the series are 
truly radial. Such is the structure in the largest valves of 
A. Ralfsii, A. Ehrenbergii, A. Barklyi, etc., but the markings are 
just as truly fasciculate as in the smallest form's, though the 
fasciculi are not so patent. No amount of variation of the 
kind described, therefore, is in itself of importance in classification. 
But great irregularities in the arrangement of the markings 
prevail, and there is' perhaps no other genus in which valves 
of one and the same species present such different aspects. 
While one valve may have the interfasciculate rays very distinct, 
all starting from a circular central ring of granules, and all the 
series well defined, the next may present at first sight a very 
different aspect, owing to the denseness of the granulation, and 
in yet another much of the appearance of regularity may be 
lost owing to its sparseness. This is especially noticeable in the 
centre of the valve, where there may be a regular area, with 
perhaps a few granules in the centre, while in other cases there 
may be no definite area at all. Usually the interfasciculate rays 
stop short at a little distance from the centre, but in the small 
valves of A. Ehrenbergii from Oran, as Mr. Rattray points out, 
they cross each other. Another point of variation is the width 
of the blank areas along the sides of the interfasciculate rays. 



32 W. M. BALE ON SOME OF THE DISCOID DIATOMS. 

Jl, fasciculatus Castracane is distinguished by the notable width 
of these areas, but the character is of no specific importance. 
A, Ehrenbergii often exhibits such areas, and I have seen them 
in one valve while the other in the same frustule showed 
scarcely a trace of them. They may even exist on only a part 
of a valve. So far as Castracane's figures show, there is nothing 
to distinguish his species from A. Ehrenbergii. 

A frequent phenomenon in the genus is the occurrence of 
regular or irregular blank areas crossing the rows of puncta, 
often in a sub-concentric fashion, and A. crassus is a form in 
which the apparent irregularity of the markings from this cause 
has been made a ground for specific distinction. Yet both Van 
Heurck and Peragallo, who admit the species, show by their 
figures that the markings are as in A . Ehrenbergii, except in so 
far as the granules ard obliterated over certain irregularly sub- 
concentric areas. I find nothing here to warrant the separation 
of the form as a distinct species. 

The interfasciculate rays are also liable to interruptions, and 
Castracane has described a species A. complanatus in which 
they are said to be wanting, though the valve is of the ordinary 
fasciculate type. I greatly doubt the correctness of this, not 
merely on a priori grounds, but owing to Rattray's identification 
of this species with the form distributed by Moller as A. Ralfsii. 
Now the " A. Ralfsii 1 ' of my Typen-Platte is simply one of the 
forms of A. Ehrenbergii in which the fasciculation is similar to 
that of A. Ralfsii, and which abound in Cuxhaven and Ichaboe 
guano material. The interfasciculate rays are certainly not 
wanting, though doubtless obscure and irregular in parts. Many 
otherwise similar valves occur in which there is no noticeable 
irregularity of these rays. 

The general aspect of the valve depends largely on the position 
and distance of the granules relatively to the others in the same 
und adjacent rows of the fascicle. In A. Barklyi the granules of 
each row are very close to each other, but not so close to those 
of the next rows ; the rows therefore remain distinct from each 
other even to the border. In A. Ralfsii type and var. sparsus 
the granules of adjacent rows are mostly side by side, so that 
they form straight lines crossing the fascicles, thus having as a 
whole a sub-concentric disposition ; they are also distinctly 
separated from each other. In A. Ehrenbergii there is much 



W. M. BALE ON SOME OF THE DISCOID DIATOMS. 33 

variation, the granules often forming irregular zigzag lines 
crossing the fascicles; generally, however, the tendency is for 
the granules of adjacent series to alternate with each other, and 
also to be somewhat crowded, so as to form a quincuncial 
arrangement, which in any case prevails towards the border. 
In A. rex the alternate arrangement is much more pronounced, 
and as the granules are crowded equally all round the markings 
form a very regular areolation over the greater part of the 
valve. 

The appearance of the granules themselves varies remarkably 
in the same species. In A. Ehrenbergii some valves show them 
in the best focus as minute, dark, sharply defined circles, while in 
others they are more pearly, and show, much more readily, a 
central black spot. When crowded, especially towards the 
border, they form a distinct areolation. In A. rex the latter 
type predominates, but near the centre the granules are more 
pearly. In A. Barklyi and A. ellipticus they vary much as 
in A. Ehrenbergii. And in all these species they appear some- 
times as dark, well-defined puncta. Peragallo has figured a form 
which he calls A. nebulosus, and which is practically a hyaline 
valve of A. Ehrenbergii with fine puncta instead of granules, also 
a corresponding form with the puncta arranged like the granules 
of a typical A. Ralfsii. He thinks these valves are probably the 
result of cleavage, of the correctness of which opinion I think 
there can be no doubt. Corresponding forms of A. Barklyi are 
found in hundreds in slides of that species, often so delicate and 
colourless that they become invisible on a slight alteration of the 
focus. How many layers has a valve of A. Barklyi% When 
manipulating one under the microscope I saw it divide into 
three, one extremely thin and hyaline, and another somewhat 
thicker, but still less robust than the main disc. Here the 
question of colour comes in for consideration, for it is probable 
that the colour as well as the appearance of the granules depends 
more or less on the " state " of the valve whether it consists of 
more than one plate for instance, or whether the two plates 
include a film of air between them. A. rex is the most brightly 
coloured form I have seen, having the colours in sharply defined 
zones. A. Ehrenbergii is usually blue, green, purple, or brown, 
often showing more than one colour, but not in sharp zones. A . 
Barklyi varies much in the same way, but is exceptionally liable 
Journ. Q. M. 0., Series II. No. 72. 3 



34 W. M. BALE ON SOME OF THE DISCOID DIATOMS. 

to exhibit a dark, semi-opaque aspect. But all these species 
usually include forms of the same size, contour and arrangement 
of markings, but of a soft brown colour, uniform throughout 
or nearly so, and generally with fine punct'a. Are these complete 
valves, or secondary plates, or primary plates from which the 
secondary ones have been detached ? Some of these brown discs 
have the silex of the subulate areas so thickened as to appear 
black under a low power. Valves of A. Ehrenbergii with 
sharply defined granules and clear, distinct subulate areas mostly 
appear blue under low powers, with the subulate spaces white. 
Others, such as that described above, from Holler's Typen-Platte, 
are more commonly green or purple, and show no white streaks, 
though having large subulate areas, the substance of the valve 
itself appearing to have a dusky tint. The bright colours of 
these species can only be seen when dry or mounted in balsam 
or a similar medium, while in water they are colourless. 

No other diatom known to me presents such endless variety 
of marking as A. Barklyi, and occurring, as it does, in such 
profusion, it is especially suitable for a study in variation. This 
diatom is of interest as being probably the first to be named in 
Australia, it having been described by Dr. Coates in the Trans- 
actions of the Royal Society of A^ictoria for 1 860, under its 
present name. Rattray incomprehensibly calls it " Actinocyclus 
Barklyi (Ehr.) Grun.," though he knew that it was named by 
Coates, and not by either of the authors cited. He quotes a 
reference to it in the Q. J. M. S. for 1861 (wrongly quoted as 
"Plate CXXXVIII." instead of "Page 138 "), but does not refer 
to Coates' original description. It is distributed by Moller under 
the name A. dubius Grunow. It is one of the largest of the 
genus (perhaps the largest), specimens in my slides attaining a 
diameter of 0*24 mm., or more than double the maximum size 
assigned to it by Rattray. 

In normal valves the fasciculi are arranged much as in A. 
Ralfsii, but great variety exists in the denseness or otherwise of 
the granules, which, as in A. Ehrenbergii, also vary greatly in 
sharpness. But it is in individual departures from the normal 
arrangement that the tendency to variation exhibits itself in 
such an extraordinary degree. In many cases the markings are 
interrupted at a uniform distance from the centre, so as to form 
a ring, and several such concentric rings may exist on one valve, 



W. M. BALE ON SOME OF THE DISCOID DIATOMS. 35 

dividing it into zones. Sometimes the markings are denser on 
one of these zones than elsewhere. Very often the zones form 
hyaline bands on which the granules are wanting, and the 
structure may be further complicated by the addition of radial 
hyaline bands, e.g. two hyaline zones may be joined by a number 
of equidistant radial hyaline areas so that the space between 
them is divided into a circular series of sub-rectangular com- 
partments ; or a broad circular zone may be filled with hyaline 
patches of all sorts of irregular shapes. The radial series of 
granules may be all curved in a spiral fashion (a variation 
which also occurs in C. Ehrenbergii), and I have specimens in 
which the central portion, as far as the first circular interruption, 
has the moniliform series all contorted in the most extraordinary 
manner. As in A. rex, etc., the subulate areas may be either 
darker or lighter than the rest of the valve. There may be a 
small central area, or the whole centre of the valve may be 
sparsely and irregularly marked. 

I find that in some slides concave and convex valves are mixed 
about equally, leading to the conclusion that the two forms 
represent opposite valves, as in A. rex, but in other gatherings 
I find many concave valves to every convex one. Rattray de- 
scribes the valves as flat in the centre and otherwise convex, but in 
numerous cases the convexity (or concavity) is uniform throughout. 
Asteromphahis. In this genus the lines which radiate from 
about the head of the centro-lateral area to the apices of the 
areolate compartments have been assigned too much value in 
classification. Whether they originate from a single point, or 
whether they bifurcate, is absolutely immaterial, and the presence 
of geniculate bends in their course is, in some species at least, 
equally unimportant. A. Hookeri, which is not rare in one of the 
"Challenger" Antarctic soundings, illustrates this. The forms 
with six, seven, eight and nine rays, which represent four of 
Ehrenberg's "species," also a ten-rayed form, occur in slides 
which I have prepared from this material, and 1 find the 
geniculations of the radial lines very marked in some valves, 
while others show no trace of them ; others again exhibit a mixed 
condition. A good deal seems to depend on the size of the valve, 
the geniculate lines being most common in the smaller ones. 

Certain species are subject to variation in the outline. 
A. Cleveanus, as figured by Schmidt, has a rather narrow ovate 



36 W. M. BALE ON SOME OF THE DISCOID DIATOMS. 

form, but in mud from Manila it has a broader outline, and 
I found one valve perfectly circular. 

Actinoptychus. This genus is distinguished by its valves being 
divided into six or more radial cuneate compartments, which are 
alternately raised and depressed, the markings also differing (in 
normal valves) on the elevated and depressed areas. On what 
we may call, for want of a better term, the primary areas 
{Hauptfelder of Schmidt), the coarse markings are usually more 
robust, and often of different form, from those on the secondary 
areas (Nebenf elder of Schmidt) ; further, the primary areas 
usually bear a tooth or process near the margin, with, in some 
species, a radial line connecting it with the umbilicus ; while the 
secondary areas sometimes terminate in a submarginal hyaline 
band, which is not found in the primaries. The fine striation 
also is commonly different on the two sets of compartments. 
The striation is generally fairly uniform within the limits of 
a species, but the secondary markings, consisting of hexagonal 
or irregular reticulation, or systems of branching veins, is most 
variable in its distinctness, and is often wanting. When this 
occurs it is generally assumed to be the result of the detachment 
of the separate layer of the valve which is thus marked, but in 
view of the fact that different valves exhibit every possible 
degree of obsolescence of these markings, I have no doubt that 
in many cases they have not been developed. 

Among the characteristics to which too much importance has 
been attached in classification are the number of areas, the 
substitution of primary for secondary areas (so that all the areas 
are alike), the presence or absence of the secondary markings, 
also of the lines connecting the umbilicus with the processes, and 
the presence of small variations in the striation. The adoption 
of these purely artificial distinctions has led not only to the 
undue multiplication of specific names, but, what is worse, to the 
lumping together of forms which are by no means closely related. 
In several species there are six areas, a number which is 
rarely, if ever, departed from. Such are the forms composing 
the group of which A. boliviensis is typical. In the majority of 
species there is no constant number; for example the beautiful 
A. Heliopelta, valves of which usually have six, eight, ten, or 
twelve areas (constituting Ehrenberg's four species of Heliopelta), 
while more rarely there are fourteen or sixteen. A. undulatus, 



W. M. BALE ON SOME OF THE DISCOID DIATOMS. 37 

the most widely distributed species, is found in most localities with 
six areas only, yet in some Calif ornian deposits it occurs freely 
with up to eighteen areas, possibly more. 

A. undulatus is a species which well illustrates the tendency of 

the genus to vary in several directions, but the variations are 

so numerous and so closely linked, and their relationships so 

obvious, that they have not been made the basis of so many 

pseudo-species as might have been expected. I have noted about 

twenty-five forms sufficiently distinct to admit of their being 

separated for convenience of cataloguing, but few of them are so 

characteristic as to constitute definite varieties. In forms of 

average size, which may be considered fairly typical, the secondary 

markings are commonly about four in O'Ol mm., while in the 

var. microsticta of Grunow, there may be about seven, and in 

large forms like forma maxima Schmidt, there are only one and 

a half to two. The reticulation may be either hexagonal or 

irregular, robust or faint, and sometimes entirely wanting. The 

sub-marginal processes are said to be sometimes absent ; in fact, 

both W. Smith and Yan Heurck appear to regard this condition as 

typical, but I have not seen specimens without some trace of them. 

(The obsolete genus Omphalopelta comprised the valves with 

processes.) The processes may be very small, appearing merely 

as a slight thickening of the border, or may be placed a little 

farther in, presenting a somewhat irregular keyhole-shaped 

aspect. In many forms the secondary areas have on their 

margin a small hyaline patch in the corresponding position to 

that occupied by the processes in the primaries. On both sets 

of areas the outermost portion, immediately adjoining the margin 

proper, usually bears radial lines, being continuations of the 

boundaries of the last row of secondary markings, which, like the 

secondary markings generally, are most robust on the primary 

areas. The rim may be smooth, or may have few or many 

minute apiculi scattered over it. The puncta which compose the 

striae of the primary areas are arranged in quincunx, so that the 

striation is the same as in Pleurosigma angulatum, but those of 

the secondary areas form two sets of diagonal striae cutting each 

other at right angles, as in P. formosum. Schmidt describes as 

A. biformis valves in which these two sets of striae meet at 

rather less than a right angle, so that a third set is visible, 

closer than the other two, and crossing the area transversely. 



38 W. M. BALE ON SOME OF THE DISCOID DIATOMS. 

Some valves which I have seen with this character were in all 
other respects similar to normal valves of A. undulatus, among 
which they occurred, and I see nothing to justify their separation, 
the slight divergence from the rectangular arrangement of the 
striae being no more than is often found in P. formosum. Some- 
times the striae meet at more than a right angle, so that the 
third set is radial instead of tangential. If Schmidt's species 
were accepted, this should make another species ! The striae are 
sometimes nearly or quite obliterated on small patches at the 
outer angles of the secondary areas, and occasionally along the 
margins ; in some forms again they are wanting or represented 
only by a few scattered puncta on a great part of those areas. 
The umbilicus varies greatly in size, and may be either hexagonal 
or may have three concave sides. Much variation exists in the 
extent to which the areas are inflated, or, in other- words, in the 
depth of the undulations. 

A consideration of the variations of this diatom will show how 
many features there are which, met with in isolated forms, may 
lead to the undue multiplication of species. 

In several species, perhaps in the genus generally, there is 
a tendency to produce valves in which the secondary areas or 
" Nebenfelder " are replaced by primary ones or " Hauptfelder," 
so that all the areas become alike, except in their elevated or 
depressed condition. Van Heurck has figured such a form of 
A. undulatus the forma sexapjiendicidata, which he says may 
co-exist in the same frustule with the normal form. He refers 
only to the presence of a process on every area, and does not 
mention that the areas are otherwise modified, which, however, 
I have always found to be the case. Other varieties of 
A. undulatus exhibit the same tendency ; thus the large forma 
maxima found in the Nottingham deposit is accompanied by its 
"forma sexappendiculata" as also is an equally large variety 
which only differs from it in the strongly apiculate margin. In 
all these cases the compartments all correspond exactly with the 
normal primary areas, both in the striation and the coarser 
secondary markings. There may possibly be varieties with this 
as the usual condition, as I have found one or two such forms 
sparsely distributed in material where I noticed no typical valves 
to which they might correspond. 

In A. Heliopelta also valves are formed in which all the areas 
are alike, instead of alternately primary and secondary. 

It is to be noted that in all species where this phenomenon 



W. M. BALE ON SOME OF THE DISCOID DIATOMS. 39 

occurs it is always the primary area, with its process, which is 
duplicated ; we never see valves with all the areas alike and 
having the distinctive markings of the secondary ones. 

Notwithstanding that it has been recognised that in A. undu- 
latus the variation in question has no specific importance, being 
found, in fact, in frustules otherwise normal, a parallel variation 
in other cases has been made a ground for the foundation of new 
species, even by observers as recent as Grunow and Schmidt. 
Such instances are A. Janischii Grun., which, as I shall 
demonstrate, is only a state of A. splendens, and A. Molleri 
Grun., which is a form of A. adriaticus Grun. Van Heurck says 
of A. Janischii that it " se distingue de toutes les autres especes 
du genre en ce que la valve a toute juste moitie autant 
d'ondulations que de divisions, de facon qu'une elevation n'est 
suivie d'une autre elevation que pres da deuxieme appendice 
suivant. Une espece analogue mais plus petite est V A. Jfolleri 
d'Adelaide, qui se distingue en outre par sa structure plus 
delicate et l'absence d'une ligne mediane." This is simply 
equivalent to saying that each area, instead of each alternate 
area, bears a process, and it is surprising that the writer did not 
observe that the character referred to as so exceptional was no 
other than he has figured in the same plate in the forma 
sexappendicidata of A. undulatus. 

A. glabratus Grunow and A. Janischii Grunow are, in part at 
least, forms of A. splendens, but there is a difference in the 
relationship which they bear to that species, A. glabratus 
simply consisting of valves wanting the secondary markings, 
while A. Janischii is an internal disc. A. splendens commonly 
has a distinct secondary layer showing more or less branching 
venation, with the typical distinction between primary and 
secondary areas, but a gathering usually includes a propor- 
tion of valves in which the secondary layer is wanting ; and 
although there is every possible gradation, the smooth valves 
have been described as a doubtful species, under the name of 
A . glabratus. Also accompanying them are valves in which all 
the compartments bear processes, and to these the name 
A. Janischii has been given, Janisch having figured one of 
them (as Halionyx vicenarius) in his paper on diatoms from 
guano. Tn Peru guano A. splendens is one of the commonest 
species, and the typical valves, with their glabratus-iovms and 
Janischii-iovms, are readily obtained. In a Cuxhaven gathering 
I also find all three forms together. And in a slide of Thum's, 



40 W. M. BALE ON SOME OF THE DISCOID DIATOMS. 

which contains a very robust variety, all three forms are 
similarly associated. In the valves described as A. Janischii 
the marginal sculpture differs somewhat from that proper to 
A. splendens, but this is a necessary concomitant of the substi- 
tution of primary for secondary areas. In A. splendens, as in 
several other species, the secondary areas terminate in a sub- 
marginal hyaline band, which encroaches slightly on the primary 
areas at each side of it. When, however, all the areas have the 
same structure, this band is wanting, all except the small portion 
which properly belongs to the primary areas, so that a small 
rounded hyaline patch opposite the edges of the compartments is 
all that remains. 

The relationship between these forms has always appeared to 
me obvious, as it evidently did to Ralfs, who describes A. splendens 
as having a tooth on each compartment, or sometimes only on 
alternate compartments. In order to obtain actual proof of this, 
however, it occurred to me to examine some Peru guano 
cleanings which had furnished numerous slides, but in which the 
complete frustules of A, splendens, where they occurred, had been 
left. I picked out ten of these and mounted them in balsam, 
with the result that I found that three out of the ten contained 
valves of the so-called A. Janischii, each being included in a 
frustule between two of the normal valves. In all cases where I 
have examined whole frustules of A. splendens I have found that 
the two valves were either alike in the number of areas, or one 
valve had a pair more than the other. Thus, if one valve had 
sixteen areas it could be predicated that the other would have 
fourteen, sixteen or eighteen. Where an internal disc was 
found (A . Janischii) it had the same number of areas as one of 
the outer valves. In the slide referred to one frustule had the 
outer valves with fourteen and sixteen areas respectively, and the 
internal disc with sixteen ; another had the outer valves with 
sixteen and eighteen, and the inner with eighteen ; and the third 
had twenty throughout. The areas of the inner disc have the 
processes rather smaller than those of the outer valves, and 
nearer the margin. Though the inner disc is usually smooth, 
like the so-called A. glabratus, this is not invariably the case. I 
have a specimen covered with reticulations as distinct as in the 
typical valves. 

In Van Heurck's opinion several genera, as well as species, 
have been founded on mere internal valves of various species of 
Actinoptychus (as also of Asterolampra). Such are Debya and 



W. M. BALE ON SOME OF THE DISCOID DIATOMS. 41 

Gyroptychus, Debya being an internal disc of A. undidatus, very 
unlike the outer valves, and found by Van Heurck inside the 
normal frustules. The A. jjellucidus Grunow, figured in Van 
Heurck's synopsis, PI. 123, fig. 1, is, as will be obvious to any one 
who compares it with the figure of A. Heliopelta in the same 
plate, merely a valve of the latter with the border wanting and 
the secondary reticulation undeveloped. In a genus-slide by 
Thum I have several such valves, but for the most part they 
retain a little more of the border, showing the origin of the 
spines, and some of them also have the secondary markings more 
or less distinctly indicated. 

In many marine gatherings from Port Phillip a form of 
A. adriaticus is found in great profusion, of which a specimen is 
figured in Schmidt's Atlas, PI. 153, fig. 14. It varies greatly in 
the distinctness or otherwise of the secondary markings, and 
especially in the presence or absence or fragmentary condition of 
the narrow radial lines which in the typical A. adriaticus, as in 
A . splendens, run outward from the umbilicus, or near it, to the 
processes. In most slides a few specimens may be found with all 
the areas alike, and a process on each, and it is this form which 
has received the name of A. Molleri Grunow. 

Normally the areas are arched at the ends, as shown in Van 
Heurck's figures, the secondary ones being shorter than the 
primary, with a wide hyaline band outside them, but as in the 
form called A. Molleri they are all primary areas, and conse- 
quently of the same length, the hyaline band is reduced to a small 
triangular area at the junction of every two compartments with 
the margin. All the variations of marking which occur in the 
normal valves are found equally in this form, and their specific 
identity is obvious. In reality, this so-called A. Molleri is the 
true A. adriaticus described by Grunow, his original figure 
showing a valve with processes on all the areas, and exactly the 
same marginal sculpture as described above. It is true A. Molleri 
is supposed to be without the radial lines to the processes, but 
Grunow recognised in his original description of A. adriaticus 
that these lines might be present or not, in which he was 
certainly correct. 

These radial lines, however (sometimes called pseudo-raphes), 
appear to be considered by Van Heurck as distinguishing 
A. adriaticus from A. vulgaris, though he admits a possible 
exception in A. adriaticus var. pumila. In the common 
Australian form, however, it is obvious that the presence of 



42 W. M. BALE ON SOME OF THE DISCOID DIATOMS. 

these lines has no specific or varietal significance whatever. 
Almost every gathering shows valves both with and without 
them, and innumerable specimens exhibit an intermediate con- 
dition, i.e. where the lines are more or less broken, or where they 
are present on some of the primary areas of a valve and not on 
others. They are scarcely ever complete, but generally stop 
short of the umbilicus, as in the var. balearica. Valves without 
them are otherwise identical with those possessing them, having 
exactly the same range of variation in other respects, and this 
applies equally to the so-called A. JIdlleri. 

While reliance on such characters as the foregoing leads to the 
improper separation of allied forms on the one hand, it tends in 
other cases to the opposite error. Thus several varieties of 
A. glabratus have been described, and while some are, as before- 
mentioned, only smooth valves of A. splendeiis, there are others 
which, so far as I know, cannot be identified with any special 
form of that species, and which may probably be themselves 
entitled to specific rank. A. vulgaris also, as generally under- 
stood, includes forms which have really no close relationship. 
One such form is nothing but A. undulatus^ as it is found in 
Redondo Beach and other deposits, with mostly fourteen areas. 
The deposit mentioned contains numerous valves of the ordinary 
form, with six areas, a few with eight, ten and twelve, a good 
many with fourteen and a few with sixteen and eighteen. The 
structure of these is absolutely identical with that of the six- 
rayed forms, and it is as absurd to separate them as it would be 
to separate forms of A. Heliojjelta with six areas from those with 
more. Other forms commonly ranked under A. vulgaris are 
simply valves of A. adriaticus with the pseudo-raphes wanting, 
as already described, while others seem to be similar, but with 
deeper and more abrupt undulations. The undulations in 
A. adriaticus are very shallow, so much so that Grunow origin- 
ally described it as flat ; but in view of the considerable variation 
in this respect found in the valves of A. undulatus and other 
species, the character would seem to be of doubtful importance. 

Probably the nearest approach to a really flat condition is 
found in the three-sided A. mari/landicus, in which the six areas 
show a very slight difference of level near the centre only, else- 
where blending with each other imperceptibly. This species has 
a more or less distinctly three-sided umbilicus, and appears to be 
identical with the Symbolophora trinitatis of Ehrenberg. Ralfs 
has argued against this view on the ground that >S'. trinitatis is 



W. M. BALE ON SOME OF THE DISCOID DIATOMS. 43 

circular, while A. marylandicus is three-sided, but in Atlantic 
City slides valves of the latter species are found in which the 
divergence from the perfectly circular form is scarcely perceptible, 
so the objection falls to the ground. 

It is sometimes stated as a character of the genus that the 
depressions of one valve correspond to the elevations of the other, 
so that the frustule is radially undulated as a whole. That this 
is not alwavs the case is evident from the fact that the two valves 
have often a different number of areas. But I find on comparing 
a number of species that there is considerable variation in regard 
to the undulations. First we have forms in which the undula- 
tions extend to and include the rim itself, so that one valve 
necessarily fits into the other. A striking example is A. trilingu- 
latics, in which the whole valve is so strongly undulated that only 
three points of the margin can be seen at any one focus. Then 
we have such species as A. undulatus and A. Heliojwlta, in which 
the undulations do not extend outward to the margin. Apart 
from the border itself, the sub-marginal zone is about on a level 
throughout, but the one set of areas is inflated as much above 
that level as the other is below it. The border itself slopes down 
rather steeply, but the depressed areas often reach as low a level 
as the extreme margin. Still, the width of the hoop ensures that 
such valves may be placed with the depressions opposite each 
other without coming into contact. Lastly, in A. splendens the 
depressions do not reach as low as the margin, while the eleva- 
tions rise considerably above it ; even with a narrow hoop, 
therefore, there is no question of the depressed areas of opposite 
valves clashing. 

According to the definitions of Ralfs and Yan Heurck, a 
character of the genus is the division of the valve into equal 
cuneate segments, which would exclude from it the A. hispidus 
Grunow (Van Heurck, Synopsis, PI. 123, fig. 2), a species which 
is described as having narrow elevated compartments alternating 
with wide depressed ones. I believe, however, that the so-called 
elevated compartments of A. hisjndus are not compartments at 
all in the same sense as those of Actinoptychiis ; neither are they 
elevations, but only appear so owing to having depressions on 
each side of them. The valve is a shallow cone, by far the 
greater part of which is occupied by about eight or nine broad 
radial cuneate areas, all of which are depressions. The linear 
rays or ridges are simply parts of the surface not included in the 
depressions, but dividing them. These rays slope down evenly 



44 W. M. BALE ON SOME OF THE DISCOID DIATOMS. 

from the umbilicus and join the sub-marginal zone without any 
interruption of the structure, which indeed is similar all over the 
valve, except the narrow hyaline border. The valve is very thin, 
covered with very delicate striae, crossing each other obliquely, 
and most easily seen on the narrow rays. The secondary 
markings consist of a fine, delicate, irregular reticulation, at the 
angles of which are dark points or apiculi, which are larger and 
darker on the narrow rays and sometimes round the inner border. 
On each of the linear rays, near the border, is a minute process. 
In Grunow's figure both the cuneate areas and the dividing rays 
are abruptly truncate at the border, but my specimens do not 
agree with this, as the narrow rays widen out in a regular curve 
towards the border zone, with which they are continuous, the 
cuneate areas having of course their outer corners rounded off 
correspondingly, while they do not quite reach the border. Owing 
to the thinness of the valve, however, and the depressions being 
by no means abrupt at the outer ends, this character might often 
pass unnoticed, unless the valve happens to be lying obliquely, 
when it becomes more conspicuous. Possibly my specimens, which 
were found in recent gatherings from Port Phillip, may differ 
specifically from Grunow's guano specimens, but the late 
Mr. Comber considered them the same. 

I think the characters by which this species is distinguished 
from all others of the genus are such as to entitle it to at least 
the rank of a sub-genus, for which I would suggest the name 
Radiodiscus. It is possible, however, that it may be brought 
under the genus Actinodictyon Pantocsek, but I am uncertain 
of the affinities of that genus, of which I have seen no specimens. 

I have a single valve, apparently belonging to A. hispidus, 
which differs in several respects from the usual form. Its 
depressions are extremely slight, there are no secondary markings 
and no apiculi, and the cuneate areas terminate in a hyaline 
band, as in A. splendens, etc.; it also has exceedingly narrow 
lines (pseudo-raphes) on the narrow areas ; the border is wanting. 
It may be a varietal form, or possibly an internal disc, but its 
pseudo-raphes and hyaline bands seem to indicate a closer affinity 
with such forms as A. adriaticus than would be inferred from the 
typical form. 



Journ. Quckett Microscopical Club, Ser. 2, Vol. XII., No. 72, April 1913. 



45 



SOME NOTES ON BRITISH FRESHWATER RHAB- 
DOCOELIDA A GROUP OF TURBELLARIA. 

By Henry Whitehead, B.Sc. 

(Read January 28th, 1913.) 

Plate 4. 

The members of the group Rhabdocoelida are very similar as 
regards appearance, shape and movements to the Infusoria, 
though they are generally much larger and their complicated 
internal structure enables them to be distinguished at a glance. 
The Rhabdocoelida form a branch of the group Turbellaria, 
to which the larger Planarians found in fresh water also belong. 
The Turbellaria, in turn, together with the Liver-flukes and 
Tape-worms, are included in the phylum Platyhelminthia 
or Flat-worms. 

The British marine Turbellaria have been monographed by 
Prof. Gamble (12), and our President has taken an active part in 
the study of the land Planarians of Australasia. The freshwater 
Turbellaria have apparently received but little attention in this 
country, though Prof. Gamble publishes a list of British species 
in the Cambridge Natural History (14). 

As the larger freshwater Planaria (Tricladida) cannot be 
regarded as microscopic objects, and are therefore of no special 
interest to the Club, the writer proposes, in this paper, to deal 
only with the group Rhabdocoelida. 

Yon Graff has written two monographs on this group, and has 
devoted much time to valuable work on anatomical features ; 
and it is chiefly from these sources that the information con- 
tained in this paper has been derived. 

The writer does not propose dealing in detail with the 
anatomy, but rather to deal with the Rhabdocoels from a general 
point of view, emphasising matters of particular interest to the 
field naturalist. 

The freshwater Rhabdocoels vary in size from 1/2 5th to half 



46 H. WHITEHEAD ON BRITISH FRESHWATER RHABDOCOELIDA 

an inch in length. They are generally found in ponds, lakes 
and ditches, and less frequently in running water. Like many 
other microscopic inhabitants of ponds, they appear in great 
abundance at certain seasons of the year and then suddenly 
disappear. 

The body is more or less transparent, slightly flattened, and is 
provided with cilia. The Turbellaria are remarkable for peculiar 
secretions given off from the epidermis. These secretions are of 
two distinct kinds one a mucous fluid, and the other con- 
sisting of very small solid bodies, or rhabdites, which, on coming 
in contact with the water, produce mucus. Several forms of 
rhabdites have been described (spindle-shaped, rod-shaped, egg- 
shaped and spherical). They are formed in special glandular 
cells which lie beneath the epidermis, and the rhabdites pass to 
the surface by means of minute ducts. 

Another interesting feature is the presence, in certain species, 
of nematocysts similar to those found in Hydra.* 

The Rhabdocoels are provided with a mouth, a pharynx and 
an unbranched, sac-like gut. The position of the mouth varies 
and affords a valuable generic character. It may lie at the 
extreme anterior or in a median position anywhere along the 
ventral surface as far down as two-thirds of the body length. 

The excretory system consists of renal organs which are, in 
some cases, somewhat complicated in structure. 

The nervous system is simply, and comprises a two-lobed brain 
and a pair of nerves running along the body close to the ventral 
surface. In some species the pigmented eyes are clearly defined, 
in others the eye pigment is scattered, and in some cases eyes 
are absent. 

Some of the freshwater Rhabdocoels have at their anterior 
end pit-like depressions which contain cilia (PI. 4, fig. 3, cp). 
The ciliated pits rest upon a group of ganglion cells which are 
connected with the brain. Similar structures are found in 
Nemertine worms, and some zoologists consider that this 
suggests affinity between the groups. Another interesting organ 
is the statocyst, which is present in some species. This consists 
of a cavity containing fluid, in which is suspended a highly 

* Mr. Scourfield has recently called my attention to a paper by C. H. 
Martin (20) on this subject. The author shows conclusively that the 
nematocysts are derived from the prey upon which the Turbellarian feeds. 



A GROUP OF TURBELLARIA. 47 

refractive particle of calcium carbonate the otolith (or statolith). 
The statocysts serve as organs of equilibration. 

Reproduction is, in most cases, sexual. The animals are 
hermaphrodite, but the male organs ripen first. The sexual 
organs are very complicated, and the details of their structure 
are of great value in classification. On this account it is often 
impossible to determine the species of immature individuals, and 
sometimes it is necessary to have specimens in both the male and 
the female stages before identification can be certain. Fresh- 
water Turbellaria undergo no metamorphosis, and newly hatched 
individuals are similar to their parents in general appearance. 

Asexual reproduction occurs only in the section Hysterophora. 
A chain of individuals is formed by the development of mouths, 
eyes, etc., at intervals along the body. Constriction of the body 
and gut then follow, and fresh individuals are produced by 
fission. The process is illustrated in PI. 4, fig. 3. Some species 
which reproduce asexually throughout the year develop sexual 
organs in the autumn. These produce eggs which lie dormant 
through the winter. 

Considerable interest has recently been aroused in certain 
green or yellow cells which are found in the bodies of some 
species of Turbellaria. The green cells contain chlorophyll and 
are able to decompose carbon dioxide in the presence of sunlight. 
Two marine species, Convoluta roscoffiensis and G. jmradoxa, 
found on the coast of Brittany, have been the subjects of detailed 
study, and the results have been summarised by Prof. Keeble in 
a little book entitled Plant- Animals. The genus Convoluta 
belongs to a group of Turbellaria, the members of which have 
not, up to the present, been found in fresh water. The green cells 
or zoochlorellae, as they are termed, are now regarded as algae 
similar to Chlamydomonas. In the case of Convoluta it is 
certain that the presence of zoochlorellae is of benefit to the 
Turbellarian, and that the relationship is a true symbiosis. 

Von Graff (17) mentions twenty-five species of freshwater 
Rhabdocoels in which green cells have been found. The fresh- 
water species containing zoochlorellae have not been well 
studied, and some zoologists doubt whether there is mutual 
benefit in the association. This aspect of the subject will, 
however, be dealt with later. 

The Rhabdocoelida live under various conditions, but generally 



48 H. WHITEHEAD ON BRITISH FRESHWATER RHABDOCOELIDA 

prefer still or gently flowing water to rapid streams. One 
species, Prorhynchus stag7ialis, is sometimes found on moist earth. 
Many of the aquatic forms are free swimmers, and may be 
captured in the net in the same way as rotifers and water-fleas ; 
others live in mud. In the latter case it is best to pour a little 
of the mud into a glass tank containing clear water, and to 
remove any Rhabdocoels by means of a pipette. They should 
be examined in a live box, and it will be found that a slight 
pressure is necessary to ensure making out their internal 
structure. They are very difficult to prepare in a satisfactory 
manner as permanent objects, and the writer has made numer- 
ous experiments with a view to narcotising them, but with 
little success. Eucaine, chloroform, ether and alcohol are of no 
use. The difficulty seems to lie in the fact that the rhabdites 
are discharged as soon as the animal is irritated, and these, of 
course, produce quantities of mucus. Moreover, the epidermal 
cells get destroyed during the process. The only satisfactory 
method of killing seems to be by means of some hardening re- 
agent, like corrosive sublimate solution, which takes effect before 
the mucus and rhabdites can be discharged. The following well- 
known method is the best. The specimen is placed in a watch- 
glass with a little water, the bulk of which is withdrawn by a 
pipette. A drop of Lang's Fluid is then delivered from a pipette 
on the side of the watch-glass and is allowed to run over the 
animal. Death is almost instantaneous, and but little shrinkage 
takes place. Even with this method the writer has not yet 
succeeded in killing species of Mesostoma without disruption. 
After remaining in Lang's Fluid from ten to fifteen minutes, 
the specimens are removed to 45-per-cent. spirit. They are 
afterwards passed through alcohol of increasing strength, stained 
with borax-carmine and mounted in Canada balsam in the usual 
way. 

Some of the Rhabdocoels appear to be entirely vegetarian in 
diet, and consume desmids, diatoms and unicellular algae. In 
fact, care is sometimes necessary to distinguish the food from 
the zoochlorellae. The latter, however, never occur in the gut. 
The majority of species take animal food, which consists of water- 
fleas, small worms, etc. 

We may now consider a few typical species which have been 
taken by the writer in the neighbourhood of London. 



A GROUP OF TURBELLARIA. 49 

Catenula lemnae (Ant. Dug.). 

Occurs in ponds and lakes, and often appears suddenly in 
considerable numbers in collections of rain-water during the 
spring and summer, and disappears as rapidly as it comes. 
It is white and thread-like in appearance, consisting of a chain 
of 2 4 individuals (rarely more) and attaining a length of 
5 mm. The body possesses a well-defined head lobe, which is 
marked off by a slight constriction and a ring of comparatively 
long cilia ; a statocyst is present. The usual mode of repro- 
duction is by fission, but sexual organs are developed when the 
pond or ditch begins to dry up. 

Microstomum lineare (Mull.) (PI. 4, fig. 3). 

This species is very similar to the foregoing, but the colour is 
yellowish or greyish brown. It is usually found in the form of 
a chain of zooids of which there may be as many as 18. The 
colony attains a length of 8 mm. Each zooid develops a pair of 
red eyes, behind which may be seen the ciliated pits. The skin 
is thickly clad with cilia. No rhabdites are present, but 
nematocysts, similar in form to those of Hydra, are present (20). 
The figure shows the manner in which new individuals arise, and 
various stages in the formation of mouths may be seen. The gut 
is common to all the zooids in the chain, until fission takes place. 
The writer has seen desmicls which had been swallowed for food 
pass along the common gut from one zooid to another. Sexual 
organs are sometimes produced, and the ripe eggs are oval in 
shape and orange or dark red in colour. 

This species is fairly common in stagnant or slowly moving 
water. It has been found in thermal springs at a temperature 
of 130 F. and also in brackish water. It moves slowly on a 
surface, but is a graceful and swift swimmer. 

Dalyellia viridis (G. Shaw) (PI. 4, figs. 1 and 2). 

Examples of this species attain a length of 5 mm., and are 
generally spinach-green in colour. The colour is due to the 
presence of algal cells Which lie beneath the epidermis. The 
body is truncated in front, widens towards the middle and 
then tapers towards the tail. There are two bean-shaped eyes. 
There is a very distinct pharynx and the gut is sac-like. 

Journ. Q. M. C, Series II. No. 72. 4 



50 H. WHITEHEAD ON BRITISH FRESHWATER RHABDOCOELIDA 

Specimens of this interesting Rhabdocoel were taken in one of 
the ponds in Richmond Park, on the occasion of the Club's visit 
on April 13th, 1912. The following week the writer took 
specimens from a pond near Chigwell Row, Essex. 

It was noticed that the animals had a number of eggs (in one 
instance 49 were counted) in the spongy body tissue, and 
individuals in this condition avoided the light. As far as could 
be ascertained, no eggs were deposited by the living animals, but, 
on death, the eggs were liberated on the decomposition of the 
body of the parent. So far none of these eggs have hatched. 

Prof. Sekera (16) of Tabor, Bohemia, succeeded in keeping 

specimens alive for some time, and the following notes are taken 

from the account of his observations. Young specimens were 

taken in ponds in March, when ice was still floating on the 

water. The animals were colourless, but as soon as they 

approached maturity, and the sexual pore developed, it was 

noticed that a few algal cells (zoochlorellae) had entered the 

body cavity by this means. Streaks of green granules then 

began to spread from this region and extend beneath the cuticle 

over the whole body, until finally the animal became quite 

green. (T would remark, in parenthesis, that mature specimens 

show distinct lines or bands devoid of zoochlorellae.) Solid 

food in the form of diatoms, rotifers, etc., was ingested during 

this period. While rapid division of the algal cells was taking 

place, they formed spherical or ellipsoid clusters, each group 

being surrounded by a colourless membrane. The membrane 

finally disintegrated and the algal cells were dispersed in narrow 

irregular lines or bands. The mature zoochlorellae showed no 

signs of an enveloping membrane. The animals exhibited at 

this period a distinct tendency to crawl towards light (phototactic), 

but sank to the bottom of the vessel at night. During the third 

week eggs were formed in the body cavity. The worms at this 

stage began to avoid the light and spent the whole day at the 

bottom of the vessel or under vegetation. During the first week 

in May the animals died off rapidly, and with the decomposition 

of the body the eggs were liberated. The algal cells were set 

free and continued to live, and developed an investing membrane, 

then passed into a resting stage, probably awaiting an opportunity 

of invading the next generation of Dalyellia. 

Prof. Sekera thinks that the alga is of little or no value to the 



A GROUP OF TURBELLAEIA. 51 

animal in the way of providing food, his reasons being that 
closely allied species, living under similar conditions, do not con- 
tain algae, and that solid food is ingested after the algal cells are 
fully developed. The writer hopes to investigate this question 
more fully, for Sekera's argument does not seem to be quite 
conclusive. 

Sir J. G. Dalyell (1) wrote an account of this interesting 
species in 1814, and states that it sometimes occurs in large 
numbers, and then suddenly disappears. He found his specimens 
chiefly in the spring, but some were found in the autumn. 

Mesostoma Spp. (PL 4, fig. 4). 

Some of the species of Mesostoma produce two kinds of eggs 
thin-shelled and thick-shelled. The thick-shelled eggs, which 
contain a large quantity of yolk, are produced in the late summer 
and lie dormant during the winter. The young hatched from 
these so-called " winter " eggs, when less than half the size of the 
parent commence to produce thin-shelled eggs with but little 
yolk. It is probable that these eggs are unfertilised ; they are 
produced in great numbers and begin to hatch in April and May. 
The young hatched from these eggs attain full development 
and produce thick-shelled " winter " eggs, which have been 
fertilised (14). 

There is some difference of opinion amongst observers as to the 
precise nature of the life-cycle in this genus. See von Graff (17). 
They vary in size from 3 to 15 mm. in length according to 
the species and condition. They live in clear, still or slowly 
flowing water and swim or creep over water-plants. Their food 
consists of entomostraca, small worms, etc., which are sometimes 
caught by means of slime threads. 

Bothromesostoma personatum (Schm.). 

Specimens of this species attain a length of about 7 mm. and 
are easily identified by two white patches which look like large 
eyes on each side of the "head." The rest of the body is either 
grey or black. The writer has taken specimens on the leaves of 
water-lilies and creeping on the surface film, at Staines and at 
the East London Waterworks. The genus Bothromesostoma is 
closely allied to Mesostoma, and like the latter produces both 
summer and winter eggs. 



52 H. WHITEHEAD ON BRITISH FRESHWATER RHABDOCOELIDA 

Gyratrix hermaphroditus Ehrbg. (PI. 4, fig. 5). 

This species appears to be widely distributed. It is about 
2 mm. in length, is almost transparent and is a rapid and 
graceful swimmer. It can easily be recognised by the com- 
paratively long stiletto at the posterior extremity. This weapon, 
although connected with the male copulatory apparatus, is 
furnished with a gland which probably secretes a poison of some 
kind and is used by the animal when attacking its prey. It has 
a well-marked proboscis, behind which are two eyes. The mouth 
and pharynx are situated near the middle. As a general rule, 
only one egg-capsule is present, and this produces one or two 
embryos. 

The field is almost unworked as regards this country. Von 
Graff records 110 species of Ehabdocoelida from Germany. As far 
as the writer can ascertain, only 30 species have been recorded 
from the British Isles. It is hoped that this short account 
mav arouse the interest of some of the members of the Quekett 
Microscopical Club in these interesting animals. 



List of British Species. 

In the following list the descriptions of the species will, unless 
otherwise stated, be found in Die Silsswasserfauna Deutschlands, 
Heft. 19. The initials H. W. after the localities denote that the 
species has been found by the author at those places : 

Sub-order RHABDOCOELA. 

Section Hysterophora. 

Fam. CATENULIDAE. 

Catemila lemnae Ant. Dug. 
Near Cork (14). 

Stenostomum leucops (Ant. Dug.). 

Common (14) ; Clare Is. (24) ; Staines (H. W.). 

S. unicolor 0. Schm. 
Clare Is. (24). 



Journ. Q.M.C. 



Ser. 2, Vol. XII., PI. 4, 




rw 



H W del. 



Rhabdocoelida. 



A GROUP OF TURBELLARIA. 53 

Fam. microstomidae. 

Microstomum lineare (Miill). 

Fresh water (14) : Chigwell : Higham's Park, (H. W.) ; 
" In all Scottish lochs " (19) ; near Dublin (21). 

Macrostomum appendiculatum (0. Fabr.) (= hystrix, 
Oe). 
Stagnant water (14) ; Clare Is. (salt water) (24). 

Fam. PRORHYNCHIDAE. 

Prorhynehus stagnalis M. Schultze. 

In Devonshire rivers (14) ; L. Lomond (19) ; Fenton 
Tower, E. Scotland (9). 

P. curvistylus M. Braun. 
Near L. Lomond (19). 

Section Lecithophora. 

Fam. DALYELLIIDAE. 

Dalyellia diadema Hofsten (18). 

Chigwell Row (H. W.). This species appears to have been 
recorded only once before, viz. in the Bernese Alps. 

D. viridis (G. Shaw) (= heUuo Miill). 

Generally distributed (14) ; Richmond Park, Chigwell 
Row (H. W.) ; Edinburgh (9). 

D. armigera (O. Schm.). 
Millport (14). 

D. Schmidtii (L. Graff). 
Millport (14). 

D. millportianus (L. Graff) (9). 
Millport (9). 

Jensenia agilis Fuhrm (= serotina, Dorner). 
Richmond Park, Epping Forest (H. W.). 

J. truncata (Abildg.). 

Abundant in fresh water (14), L. Lomond (19). 

Phaenocora (= Derostomum) punctatum Orst. 
Theydon Bois (H. W.) ; Edinburgh (9). 

Opistomum Schultzeanum Dies. 
L. Lomond (19). 



54 H. WHITEHEAD ON BRITISH FRESHWATER RHABDOCOELIDA 

Fam. typhloplanidae. 

Rhynchomesostoma rostratum (Miill). 

Widely distributed (14) ; Millport, Edinburgh (9). 

Typhloplana viridata (Abildg.) ( = Mesostoma viridatum 
M. Sch.). 
Manchester (14) : Clare Is. (24). 

Mesostoma productum (0. Schm.). 
Cambridge (14). 

M. lingua (Abbild.). 
Cambridge (14). 

M. Ehrenbergii (Focke). 

Cambridge (14). 

M. tetragonum 0. F. M. 

Cambridge (14). 

M. Robertsonii L. Graff. (9). 
Millport (9). 

M. flavidum L. Graff. (9). 
Millport (9). 

Bothromesostoma personatum. (0. Schm.). 

Preston (14) ; Staines, E. Lon. Waterworks (H. W.). 

Fam. POLYCYSTIDIDAE. 

Polycystis Goettei Bresslau. 

Nr. Abergavenny, L. Lomond (19). 

Fam. GYRATRICIDAE. 

Gyratrix hermaphroditus Ehrbg. 

Common in fresh water (14) ; Chigwell Row (H. W.) ;. 
St. Andrews (salt water) (9) ; Clare Is. (salt 
water) (24). 

Sub-order ALLOEOCOELA. 

Fam. OTOPLANIDAE. 

Otomesostoma auditivum (Pless.) ( = Monotus morgiensis 
et relictus Du Plessis). 
Deep waters of Scottish lochs (19). 



A GROUP OF TURBELLARIA. 55 

Fam. BOTHRIOPLANIDAE. 

Bothrioplana sp. ? 
Manchester (14). 

Euporobothria bohemica (Vejd.). 
Tarbet, L. Lomond (19). 

Bibliography. 
Confined to the more important works or to papers quoted. 

1. 1814. Dalyell, J. G. Observations on Planariae. 

2. 1848. Schmidt, E. 0. Die Rhabdocoelen (Strudelwiirmer) 

des Siissenwassers. 

3. 1853. Dalyell, J. G. The Powers of the Creator, vol. ii. 

4. 1865. Johnston, G. A Catalogue of the British Non-para- 

sitical Worms in the British Museum. 

5. 1867. Lankester, E. R. Planariae of our Ponds and 

Streams. Pop. Sci. Rev., vi., pp. 388-400. 

6. 1868. Houghton, W. Our Freshwater Planariae. In- 

tellectual Observer, xii., pp. 445-449. 

7. 1878. Jensen, O..S. Turbellaria ad litora Norvegiae. 

8. 1879. Hallez, P. Contiibutions a l'histoire naturelle des 

Turbellaries. 

9. 1882. Graff, L. von. Monographie der Turbellarien. I. 

Rhabdocoeliden. 

10. 1885. Braun, M. Die Rhabdocoeliden Turbellarien Liv- 

lands. 

11. 1885. Graff, L. von. Article " Planarians " in Encyc. Brit. 

Ninth Edition. 

12. 1893. Gamble, F. W. Contributions to a knowledge of the 

British Marine Turbellaria. Quart. Journ. Micro. 
Science, vol. xxxiv., p. 433. 

13. 1894. Fuhrmann. Der Turbellarien der Umgebung von 

Basel. Revue Suisse de Zoologie. 

14. 1901. Gamble, F. W. Flatworms and Mesozoa in Cam- 

bridge Nat. Hist., vol. ii. 

15. 1901. Benham, W. B. Lankester's Treatise on Zoology. 

Pt. IV. Platyhelmia. 

16. 1903. Sekera, E. Einige Beitrage zur Lebensweise von 

Vortex helluo. Zool. Anz., xxvi., pp. 703-710. 



56 H. WHITEHEAD ON BRITISH FRESHWATER RHABDOCOELIDA. 

17. 1904-8. Graff, L. vox. Das Thierreich, Turbellaria. I. 

Acoela und Bhabdocoelida. 

18. 1907. Hofsten, Nils von. Studien iiber Turbellarien aus 

dem Berner Oberland. Zeitschr. f. wiss. Zoologie, 
lxxxv., pp. 391-654. 

19. 1908. Martin, C. H. Notes on some Turbellaria from the 

Scottish Lochs. Proc. Roy. Soc. Edin., vol. xxviii., 
pp. 28-34. 

20. 1908. Ibid. The Nematocysts of Turbellaria. Quart. 

Journ. Micro. Sci., vol. lii., pp. 261-277. 

21. 1908. Southern, R. Handbook to City of Dublin. Brit. 

Assoc. 

22. 1909. Graff, L. von. Die Siisswasserfauna Deutschlands. 

Heft. 19. 

23. 1911. Ibid. Acoela, Bhabdocoela und Alloeocoela des ostens 

der vereinigten staaten von Amerika. Zeitschr. 
wiss. Zoologie, xcix., pp. 1-108. 

24. 1912. Southern, R. Clare Island Survey. Pt. 56. Platy- 

helmia. Proc. Roy. Irish Acad., xxxi. 

Description of Plate 4. 

Pig. 1. Dalyellia viridis, entire, x 15. 

2. Chitinous copulatory organ of D. viridis, X 150. 

3. Microstomum lineare, entire, x 20. 

4. Mesostoma sp., entire with thin-shelled eggs, x 20. 

5. Gyratrix hermaphroditus, entire, X 45. b c, bursa copu- 
latrix ; c, cocoon ; c p, ciliated pit ; e, egg ; g, gut ; 
m, mouth ; o v, ovary ; p, poison-sac ; p h, pharynx ; 
p r f proboscis ; s t, stiletto ; it t, uterus. 






Journ. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 72, April 1913. 



57 



THE ROTIFERA OF DEVILS LAKE, WITH DESCRIP- 
TION OF A NEW BRACHIONUS. 

By Charles F. Rousselet, F.R.M.S. 

{Read January 2%th, 1913,) 

Plates 5 and 6. 

Devils Lake, the largest body of water in North Dakota, U.S.A., 
is approximately 30 miles long by 5| miles wide at its broadest 
part, and of very irregular shape. It receives its water from 
a territory which forms an inland drainage basin extending 
northwards as far as the Turtle Mountains. 

From the records it appears that the level of the lake has 
fallen 14 feet since 1883 (when it stood at 1,439 feet above sea- 
level) and 16 feet between 1830 and 1883, making a total 
recession of 30 feet in eighty years with a corresponding shrink- 
age of the area of the lake. At the time of its highest level the 
lake had an overflow outlet at its eastern end into Stump Lake 
lying further east, and it is probable that this high-water level 
was reached many times in past centuries through periods of 
scanty rainfall succeeded by periods of unusually abundant pre- 
cipitation. In 1910 the level of the water stood at 1,425 feet 
above sea-level, but fluctuates about 4 feet between very dry 
and wet periods. The lake has had no outlet for a long period, 
and as the result of evaporation the water has become brackish, 
the salinity increasing gradually by concentration, until at the 
present time the water has a specific gravity of 1*0076 (the 
sp. gr. of sea water being 1*027). 

Besides common salt the water contains appreciable quantities 
of sodium sulphate and magnesium sulphate, carbonate and 
bicarbonate, so that it is alkaline as well as brackish, and this 
no doubt accounts for the very peculiar and remarkable Rotif erous 



58 C. F. ROUSSELET ON THE ROTIFERA OF DEVILS LAKE 

fauna it contains, which is abundant in numbers but very re- 
stricted in species. 

Since 1910 a Biological station has been established on the 
shores of the lake by the Legislative Assembly of the State of 
North Dakota, under the control of the Biological Staff of the 
State University. 

At the request of Prof. R. T. Young I have at various times 
examined samples of plankton collected by him in July 1910 and 
May 1912, and have found therein only the following seven 
species of Rotifera, the majority of them rare, strange and 
unusual forms : 

Triarthra longiseta Ehrenberg (a single specimen, possibly 

accidental). 
Pedalion fennicum Levander. {Very abundant.) 
Asplanchna Silvestrii Daday. (Very abundant.) 
Brachionus Midleri Ehrenberg. (Few.) 
Brachionus satanicus Rousselet. (Very abundant.) 
Brachionus spatiosus Rousselet. (Very abundant.) 
Brachionus pterodinoides sp. nov. (Few.) 

Two of these forms I have already described as new,* and 
have now to introduce a third still stranger species. 

The single specimen of Triarthra may have been introduced by 
accident in one of the tubes. 

Rotifera are essentially freshwater animals, and brackish or 
salt water does not suit the great majority of species; this ex- 
plains the paucity of species living in Devils Lake. 

This fact does not militate against the theory of cosmopolitan 
distribution of the class, on the contrary it confirms it, for 
Pedalion fennicum is known from brackish lakes only in Finland, 
Egypt, Central Asia, Asia Minor, etc. The presence in the lake 
of the rare Asplanchna Silvestrii suggests that the " Lago di 
Villa Rica," in Chile, from which it was first obtained, is a 
brackish lake. Perhaps Prof. Silvestri, who obtained Daday's 

* Journ. Q.M.C., Ser. 2, Vol. XL, pp. 162 and 373 (April 1911 and 1912). 



WITH DESCRIPTION OF A NEW BRACHIONUS. 59 

material, would be good enough to confirm or disprove this 
suggestion. 

Brachionus pterodinoides sp. nov. (PI. 6, fig. 1). 

This new Brachionus, of which only very few specimens were 
found, possesses a type of lorica new to the genus, and appears to 
have done its best to try to deceive the systematic student by 
making itself look as closely as possible like a Pterodina. For quite 
a considerable time I was unable to decide whether the animal 
belonged to the genus Brachionus or Pterodina until I found one 
specimen with the foot and its two small toes protruding, which 
decided the question. As will be seen on referring to PI. 6, fig. 1, 
the lorica is nearly circular in shape, greatly compressed and 
flattened dorso-ventrally, and possesses a foot-opening situated 
just below the middle on the ventral plate, a most unusual 
situation for a Brachionus, but usual in Pterodina. The dorsal 
plate of the lorica is greatly extended posteriorly beyond the 
foot-opening, and under this projecting cover the eggs are carried. 
The lorica is smooth except anteriorly, where six small ridges 
mark the continuation of the six frontal spines. The mental 
edge is a nearly straight line and without indentation. As far 
as could be made out in the few preserved specimens available, 
the internal anatomy of this species appears to be normal. In 
one specimen the wrinkled foot was extended, showing two small 
pointed toes, as shown in fig. \c. The lateral antennae protrude 
high up above the middle on each side. 

I am greatly indebted to Mr. F. P. Dixon-Nuttall for the 
three figures giving an excellent idea of the form of this new 
species and new type amongst the Brachionidae. 

Size of lorica, length 285 /x (l/89th inch), width 224 fi (1/1 14th 
inch). 

Brachionus satanicus Rousselet (PI. 6, fig. 2). 

When describing this species two years ago * I had specimens 
only which had been obtained in a plankton collection made in 

* Journ. Q.M.C., Ser. 2, Vol. XI., p. 162 (1911). 



60 C. F. ROUSSELET ON THE ROTIFERA OF DEVILS LAKE 

Devils Lake in the month of July 1910, and all these had the 
shape shown in the figure, with two long, curved and widely- 
separated posterior spines. Last year I obtained from Prof. Young 
a collection made in the month of May 1912, much earlier in the 
season, when the weather in North Dakota is still cold and the 
water chilly. Together with the fully developed forms in this 
collection I found a much smaller form, with short posterior 
spines, curved inwards and other unusual features as represented 
in PI. 6, fig. 26-/. The six frontal spines and the mental edge 
are identical with those of the larger specimens, but the shape of 
the body and the form and size of the posterior spines are very 
different, and, strangest of all, the foot-opening is situated on the 
postero-dorsal side of the lorica, a quite unheard-of position in 
this genus. My first impression was that these were young 
animals just hatched from eggs, but this is evidently not so, for 
some specimens were seen carrying their eggs at the base of the 
foot on the dorsal side, and they were therefore adults reproducing 
freely. I can only conclude that this represents a case of 
dimorphism, possibly a winter form which gradually, in successive 
generations, transforms itself into the larger form with extended 
and expanded posterior spines. In saying this I do not mean 
that the smaller forms (PI. 6, fig. 26-c) can themselves grow into 
the form of fig. 2a, but that their offspring will in a few genera- 
tions more and more resemble the larger form. Intermediate 
forms between the two types figured were not seen. In order to 
follow up this transformation it will be necessary to obtain 
plankton collections made about twice a month throughout the 
year, which at present are not available. It certainly is not 
easy to see how the dorsally situated foot-opening can change 
into the median posterior position of the larger form, but it is 
known that in the case of some Asplanchna (A. amphora, 
A. Sieboldii) the transition from humped into saccate forms and 
other changes take place suddenly, from one generation to the 
next, produced apparently through a change of diet and 
temperature, as shown by the recent researches of Dr. Arno 



WITH DESCRIPTION OF A NEW BRACHIONUS. 61 

Lange * and Prof. Powers. t Should these changes in B. satanicus 
be confirmed, it will be the first record of true dimorphism in the 
genus Brachionus. Fig. 2e and f represent variations in the 
shape of the posterior spines of the smaller form. 

Fig. 2a-f were drawn from my own preparations by Mr. F. R. 
Dixon-Nuttall, to whom I am greatly indebted for these accurate 
and beautiful drawings. 

The large form fig. 2a measures 408 /x (l/62nd inch), and 
the small form 250 /x (1/1 00th inch), in both cases including 
the posterior spines. 

Asplanchna Silvestrii, Daday. 
PI. 5, figs. 19. 

This fine and rare species was first described by Daday in 
1902,J and found by him in plankton collections made by 
Dr. Silvestri in 1899 in the Lago di Villa Rica in Chile. I have 
not been able to ascertain if this lake is brackish or not, 
Prof. Daday having no information on this point, but the 
presence therein of Pendalion fennicum seems to make it highly 
probable, for the latter species has never yet been found in 
fresh water. 

In the collections from Devils Lake I found Asplanchna 
Silvestrii in great abundance, and moreover it presented a marked 
dimorphism, and even polymorphism, for all gradations from 
plain saccate forms to fully developed double-humped animals 
were represented in the same gathering. PI. 5, figs. 1 4 
represent three of the forms. It is not possible for me to say 
w T hich of these forms appears first, or which is hatched from the 
resting-egg, and what causes these changes of form. According 
to the observations of Prof. J. H. Powers, of Nebraska Univer- 

* Zur Kenntnis von Asplanchna Sieboldii, Zool. Anz. Bd. 38, pp. 433-441, 
November 1911. 

f A case of Polymorphism in Asplanchna simulating mutation. 
American Naturalist, Vol. XL VI., 1912. 

\ Beitrage zur Kenntnis der Siisswasser Mikrofauna von Chile. Ter- 
meszetrajzi Fiizeteh, 1902. 



62 C. F. ROUSSELET ON THE ROTIFERA OF DEVILS LAKE 

sity, who has lately published an account of similar changes 
in A. amphora found by him in a brackish pool, it is caused by a 
change of diet, from vegetable to more substantial animal food, 
and even cannibalistic fare. Prof. Powers found that the 
animals hatched from resting-eggs were invariably saccate, and 
that the humped and larger campanulate forms developed from 
these. 

Asplanchna Silvestrii is a very large and powerful animal, as 
is shown by its ability to capture, swallow and digest the 
large and vigorous Diaptomus which abound in this lake ; one 
of these Copepods was seen to more than fill its stomach. 

The male was also found ; it is humped, but the side humps 
are not bind as in the humped female, as shown in figs. 5 
and 6 ; the fertilised resting-egg is represented in fig. 9. The 
jaws are of the usual type, but are different from those of any 
other species of the genus, as is shown by fig. 7. The rami 
are massive, and have a semi-circular cut-out near the tip, 
which is peculiar ; they have also a strong basal hook and 
median inner tooth. One of the rami, the one on the right 
side when the basal hooks are uppermost, has a broad flange 
near its apical tooth ; this serves as a stop for the opposite 
tooth to prevent the two rami overlapping and interlocking. 

The prominent lateral humps differ markedly from those of 
other humped species, such as A. Sieboldii and A. amphora. In 
A. Silvestrii these are bifid, having a constriction, more or less 
pronounced, above the middle of the hump, giving it a double 
rounded outline (fig. 1) ; on the dorsal side there is a pointed 
hump near the middle of the body (fig. 2). In intermediate 
forms the humps are less prominent until the purely saccate 
form is reached (fig. 3), which in shape does not much 
differ from that of A. Brightwelli. Prof. Powers has shown 
that no single animal goes through these various shapes ; they 
are born with the shape they possess and do not change it in 
their lifetime, but their jDrogeny may have a different shape 
from the parent. A young humped individual may be seen in 



WITH DESCRIPTION OF A NEW BRACHIONUS. 63 

the uterus of a saccate female. The change takes place more 
or less suddenly from one generation to the next. The general 
anatomy of A. Silvestrii follows that of other allied species, 
and but few points need be mentioned. The two gastric glands 
are large and kidney shaped, and are attached to the long and 
rather wide oesophagus. The stomach has the usual structure 
of large, dark-coloured granulated cells. The ovary has the 
form of a narrow horseshoe-shaped band with a single row of 
germ cells. An enlarged view of one of the lateral canals 
with the contractile vesicle is given in fig. 8. The flame cells 
are closely set and numerous, numbering over thirty ; the fine 
tube to which they are attached adheres for some distance 
to the nerve-thread of the ventro-lateral antenna on each 
side. 

The sense organs consist of three pairs of antennae, namely 
two on the front of the head, two dorso-lateral and two 
ventro-lateral in position, each ending in a rocket-shaped organ 
with a tuft of stiff hairs on the outside. Two finger-like, 
fleshy processes are seen, one on each side of the head close 
to the corona. Daday mentions that the animal has three red 
eyes, but I could discover only a single small cervical red eye, 
situated on the small brain. 

The male (figs. 5 and 6) is of usual structure, and has two 
lateral humps, like the male of A. amphora. 

Greatest size of female 1,150 /x (l/22nd inch) in length ; male 
408 jx (l/64th inch) ; jaws 164 fx (l/155th inch) ; resting-egg 
195 /x (1/1 20th inch) in diameter. 

I am greatly indebted to Mr. Hammond for the excellent 
figures of A. Silvestrii on Plate 5. 

It is quite possible that farther plankton collections, and 
particularly collections made amongst the aquatic vegetation 
near the shores and in the bays of Devils Lake, may reveal 
additional species of Rotifera, but a great crowd of freshwater 
forms cannot be expected to inhabit this brackish and alkaline 
lake. 



64 C. F. ROUSSELET ON THE ROTIFERA OF DEVILS LAKE. 

Explanation of Plates 5 and 6. 

Plate 5. 

Fig. 1. Asplanchna Silvestrii Daday, characteristic female with 

double humps, dorsal view, x 50. 

2. A. Silvestrii, side view, x 50. 

3. A. Silvestrii, saccate form, dorsal view, x 50. 

4. A. Silvestrii, intermediate form, ventral view, x50. 

5. A. Silvestrii, male, side view, x 68. 

6. A. Silvestrii, male, dorsal view, x 68. 

7. A. Silvestrii, the jaws, x217. 

8. A. Silvestrii, vascular system with contractile vesicle, 

x 150. 
9. A. Silvestrii, resting-egg, x 65. 

Plate 6. 

Fig. la. Braehionus pterodinoides sp. nov., dorsal view, x 196. 
,, lb. B. pterodinoides, ventral view, x 196. 
lc. B. pterodinoides, side view, x 196. 
2a. Braehionus satanicus Rousselet. Normal type, x 180. 
2b. B. satanicus, small seasonal form (winter), dorsal view, 

X180. 
2c. B. satanicus, small seasonal form (winter), ventral view, 

Xl80. 
,, 2d. B. satanicus, small seasonal form (winter), side view, 

X 180. 
2e. B. satanicus, small seasonal form (winter), variation in 

posterior spines, x 200. 
,, 2f. B. satanicus, small seasonal form (winter), variation in 

posterior spines, x 200. 



Joum. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 72, April 1913. 



Journ.Q.M.C. 



Ser. 2,Vol.Xir,Pl. 5. 



3 






^-Xr"-' 




1 






* . 









9 












A. R. Hammond del.et lith.. West,>4ewma.n imp. 

As plan elm a Silvestrii Dadcuy. 



Journ.QM.C. 



Ser. 2,Vol.XII.Pl. 6. 



la 



/ 




lb. 




F.R. Dixon -Nuttall del.adnat. 



A.R.Hammond lith.. 
West, Newman, imp. 



Rotifera. 



65 



THE PRESIDENT'S ADDRESS. 

BY-PRODUCTS OF ORGANIC EVOLUTION. 

By Prof. Arthur Dendy, D.Sc, F.R.S. 

{Delivered February 25th, 1913.) 

Plate 7. 

We are all familiar with the fact that in the manufacture 

of any particular product of human industry the raw material 

employed is rarely entirely used up, a more or less considerable 

* 

residue generally remaining over after the process is completed. 
In so far as the prime object of the manufacturer is to produce 
some one special product, the residue which cannot be employed 
for this purpose must be regarded as waste. It frequently 
happens that this waste product is a highly deleterious substance, 
the difficulty in the disposal of which may constitute a very 
serious obstacle to the successful prosecution of the industry in 
question. On the other hand, it also frequently happens that 
what were primarily waste products may prove to have a value 
of their own quite apart from the main object at which the 
manufacturer is aiming. They then cease to be merely waste 
products and become valuable by-products, perhaps even more 
valuable than the main product itself. 

Thus in the distillation of coal in a gasworks the main purpose, 
that for which the machinery and apparatus are primarily 
intended, is the production of gas, but coke and tar and other 
by-products are also produced, all of which are now, I suppose, 
applied to some useful purpose, and thus have a value of their 
own. Indeed the existence of coal-tar has given rise to a whole 
series of new industries, involving the production of almost endless 
substances, such as the wonderful aniline dyes and so forth, 
which many people will regard as far more valuable and desirable 

Jourx. Q. M. C, Series II. No. 72. 5 



66 the president's address. 

objects than the gas for the sake of which the coal was originally- 
distilled. 

The value of a by-product will naturally depend upon the 
particular circumstances of the case, and what is useless, or 
even harmful, under one set of conditions may be extremely 
valuable under another. It may be a question of labour supply 
or of transport, or it may be that the discovery of some new 
process of manufacture in a totally different industry suddenly 
creates a demand for a by-product that was previously almost or 
entirely worthless. It is perhaps not too much to say that the 
success or failure of a manufacturer in his business must in 
many cases depend upon the ingenuity that he exhibits in 
disposing of his by-products ; but the formation of such products 
in the first instance cannot be avoided, and they may go on being 
produced, and constitute a characteristic feature of the industry 
for a long time, before some new factor in the circumstances of 
the case may give them a special value of their own. It may 
well be that this may never happen at all, and the substances 
in question may simply accumulate in harmless, if unsightly, 
heaps, or, on the other hand, they may become so offensive, 
or even dangerous, as to render impossible the continuance of 
the industry which gives rise to them. 

In short, it would be difficult to exaggerate the importance 
of the part played by by-products in the evolution of human 
industries. Such industries are necessarily subjected to a severe 
struggle for existence in ceaseless competition with one another, 
and in this struggle the by-products afford abundant opportunity 
for the elimination of the least fit by the process of natural 
selection. The by-products, however, did not themselves arise 
through any process of selection, but as the unintentional and 
inevitable results of those chemical and physical changes which 
accompany the manufacture of the main product. 

We may thus look upon a human industry as an organism, 
which undergoes a process of evolution subject to the control 
of natural selection, and some of the most characteristic features 
of which are to be found in its by-products. Indeed it may 
often be recognised and identified by its by-products almost if 
not quite as readily as by the product for the sake of which 
it primarily exists. 

We must not, of course, push our analogy too far, but I hope to 



THE PRESIDENT'S ADDRESS. 67 

be able to convince you that in the evolution of living organisms 
themselves by-products have played a part not unlike that which 
they have played in the evolution of industries. 

You have probably already began to wonder why I should 
have chosen such a subject as this for an address to a micro- 
scopical club ; but the reason will now become apparent, for 
I propose to endeavour to elaborate the ideas which I have 
been suggesting to you by reference to organisms which have 
long been favourite subjects with the microscopist, and to 
characters which can only be investigated with the aid of the 
microscope. 

We shall perhaps find nowhere in the animal kingdom a more 
exact analogy to the utilisation of waste products in human 
industries than in the curious rotifer Melicerta janus. As 
you are all aware, this minute but highly complex organism 
builds for itself a beautiful dwelling-place out of pellets of its 
own dung. I do not, however, propose to dwell upon such cases 
as this, and for our present purposes I must ask you to allow 
me to interpret the term waste products, or if you prefer it, by- 
products for it is obvious that the two cannot be sharply 
distinguished from one another in a less literal manner. 

There is, in my opinion, no group of organisms better suited 
for the illustration of the fundamental principles of organic 
evolution than the Sponges. This arises from the fact that they 
combine with an essential simplicity of structure an inexhaustible 
variation in detail, and that this variation is to a very great extent 
clearly and precisely expressed in the form of the microscopical 
calcareous or siliceous spicules of which the skeleton is ordinarily 
composed. Moreover, it appears that an unusual number of 
connecting links have been preserved to the present day, so that 
we are able to trace beautiful evolutionary series in the wonderful 
spicule -forms of existing species. 

Take, for example, the siliceous spicules which are so character- 
istic of the Tetraxonida. These are probably all to be derived 
from a primitive ancestral form or archetype (fig. 1) consisting 
of four rays diverging at equal angles from a common centre, 
like the axes which connect the angles of a regular tetrahedron 
with its central point. The assumption of this regular geometri- 
cal form by a non-crystalline substance like the hydrated silica, 
or opal, of which these spicules really consist, is a very remarkable 



68 the president's address. 

fact, especially when we consider how very widely it is afterwards 
departed from on most lines of spicule evolution. It has been 
suggested that the equiradiate and equiangular tetraxon was 
originally adapted to the interstices in a system of spherical 
flagellated chambers arranged tetrahedrally. This seems probable 
enough, but in any case we can safely take this form as our 
archetype without indulging in speculations as to its origin. 

If we now imagine one ray of our archetype becoming greatly 
elongated we get a common form of " triaene " spicule known 
as the " plagiotriaene " (fig. 2), with a long arm or " shaft " 
and three short arms or "cladi," but still with all the angles 
equal. If we imagine the angles which the cladi make with 
the shaft to be increased, so that the cladi come to point forwards, 
we get the "protriaene" (figs. 5, 5a); if the cladi extend at 
right angles to the shaft we get the " orthotriaene " (fig. 3), and 
if they point backwards we have the " anatriaene " or grapnel 
spicule (figs. 4, 4a). 

All these long-shafted triaenes are typically oriented with 
the cladi at or near the surface of the sponge, and the shaft 
directed centripetally inwards, so that the entire skeleton acquires 
a markedly radiate arrangement. The cladi of the orthotriaenes 
usually form a support for the dermal membrane at the surface 
of the sponge, beneath which they are spread out tangentially, 
and their efficiency as a dermal skeleton may be greatly increased 
by their bifurcation (" dichotriaenes," figs. 6, Ga). In the case of 
the protriaenes and anatriaenes the distal portions of the shafts, 
bearing the sharp-pointed prongs or cladi, usually project for 
some distance beyond the surface of the sponge, and in this 
position they probably serve either to ward off the attacks of 
enemies or to entangle minute organisms whose decomposition 
may supply the minute organic particles upon which the sponge 
depends for its food supply and which will be carried inwards 
by the inflowing stream of water. 

A still more remarkable modification is met with in the 
" discotriaene," in which the shaft is reduced to a short peg 
inserted in the middle of a flat disk formed by fusion of the 
cladi. The entire spicule then assumes somewhat the form of 
a carpet-nail. In the genus Discodermia we find these disco- 
triaenes stuck close together all over the surface of the sponge,, 
and forming an impenetrable mail-armour. 



THE PRESIDENT'S ADDRESS. 69 

In Stelletta vestigium, on the other hand, the cladi are reduced 
to the merest vestiges, and some, if not all of them, may com- 
pletely disappear, while the shaft remains greatly elongated 
and forms practically the entire spicule (figs, la Id). Possibly 
the simple " oxeote " spicules of this and allied species (fig. 8) 
have arisen in this manner. 

An altogether different line of evolution from the primitive 
tetraxon archetype appears to have given rise to the typical 
oxeote spicules (figs. 9, 10) of the monaxonellid division of the 
Tetraxonida. Here two of the four rays of the primitive 
tetraxon have probably entirely disappeared, while the remaining 
two have become extended in a straight line with one another. 
In the typical " stylote " (fig. 11) and " tylostylote " (fig. 12) 
spicules probably only a single ray persists, so that the so-called 
organic centre is situated at one end instead of in the middle. 
In many species the oxea, styles or tylostyles become ornamented 
with sharp spinose excrescences (fig. 13). 

In most of the cases which we have so far considered it is 
easy to see that we are dealing with adaptive modifications. 
The orthotriaene, dichotriaene, protriaene, anatriaene and 
discotriaene are all obviously well suited for the fulfilment of 
their specialised and differentiated functions, and the evolution 
of these forms is more or less readily explicable in accordance 
with the well-known principle of the natural selection of 
favourable variations. The origin of the linear spicules of the 
monaxonellid forms by complete suppression of two or three of 
the rays of the primitive tetraxon is, perhaps, not so easy to 
account for as is that of the triaene series from the same 
starting-point. In both cases the determining factor was 
probably, in the first instance, the development of a radially 
arranged canal-system, requiring a corresponding radial arrange- 
ment of the supporting skeleton, which could not be obtained 
w T ith spicules of the primitive tetraxon form. That the evolu- 
tion of the necessary linear spicules has taken place along 
different paths in different cases is, however, nothing to be 
surprised at ; it is merely one of those instances of convergence 
which are quite as common amongst sponges as amongst other 
groups of the animal kingdom. 

In the most primitive tetraxonid sponges, which represent 
more or less closely the ancestral forms from which both 



70 THE PRESIDENT'S ADDRESS. 

Tetractinellida and Monaxonellida have doubtless been derived, 
we still meet with some of the earliest stages of spicule 
evolution. Take, for example, Dercitopsis ceylonica, collected 
by Prof. Herdman in Ceylon, and described in my report on 
the Ceylon sponges. Here we find the tetraxon spicule in all its 
primitive simplicity (fig. 25), but associated with it we get 
numerous diact spicules (figs. 26a 26c), evidently derived from 
the tetract by loss of two of the original rays, and clearly 
showing, by a swelling or an angulation in the middle, that 
two rays still remain. From such obvious diactine spicules as 
these, transitional forms lead the way to the comparatively 
large, straight oxeote spicules which occur in the same and in 
many other sponges, and which no longer show any trace of 
their tetraxon and tetract ancestry. 

In Dercitopsis and its relations i.e. in the Homosclerophora 
although there may be great differences as regards the size 
of the various spicules, yet we cannot, as in most of the higher 
groups, sort these spicules out into two distinct categories 
megascleres and microscleres for innumerable gradations exist 
between large and small. 

In the course of further evolution, however, the distinction 
between megascleres, or skeleton spicules, and microscleres, or 
flesh spicules, becomes very strongly marked. Both have 
doubtless had a common origin in the ancestral tetraxon 
archetype, but whereas the former are obviously adapted as the 
principal skeletal elements, and are arranged accordingly in 
the sponge, the latter are usually scattered at random through 
the soft ground substance like plums in a pudding, and neither 
in form nor arrangement show any evident adaptation to the 
requirements of the organism. 

Indeed, the microscleres are usually so extremely minute, 
requiring high powers of the microscope to make out their 
true form, that is impossible to believe that their presence can 
exercise any important influence upon the well-being of the 
sponge. Still less is it possible to believe that the particular 
shape which they may assume, which is often highly remarkable, 
can be of any consequence to their possessor. There are, of course, 
exceptions to this, as to every generalisation, and sometimes we 
find microscleres forming a dense protective external crust, as 
in the case of the " sterrasters " of Geodia, or projecting into the 



THE PRESIDENT'S ADDRESS. 71 

inhalant canals, where they may perhaps serve to filter the 
incoming water and guard against parasites, as in the case of 
the " sigmata " of Esp>erella murrayi ; but in the vast majority 
of cases it is impossible to assign any value at all to the 
presence of microscleres. Indeed, the numerous species of 
horny sponges seem to get on quite as well without these 
bodies. 

Nevertheless we find that the microscleres, when present, 
are characterised by very definite and constant forms, and many 
of them are amongst the most beautiful and wonderful objects 
that come under the observation of the microscopist. So constant 
and characteristic are they that they afford by far the most 
convenient and most reliable data for the classification of the 
tetraxonid sponges. Particular species, and even particular 
genera and families of these sponges, are characterised by the 
presence of highly specialised forms of microscleres, and in the 
case of species the characteristic form is almost invariable. 

There can be no doubt that the microscleres have undergone 
an evolution along definite lines, and one species of a genus is 
commonly distinguished from another by differences in the 
shape of these spicules, which, though constant, appear at the 
same time to be utterly trivial as, for example, the difference 
in the shape of the teeth at the small end of the " isochelae " in 
Cladorhiza pentacrinus (figs. 23, 23a) and Cladorhiza (?) tridentata 
(figs. 24, 24a). There may be several kinds of microsclere in 
the sponge, all characteristic of the species, but a single sponge 
may contain many thousands, or perhaps millions, of the same 
kind, all exactly alike in shape and size except for an occasional 
individual variation such as occurs in all organisms. 

The shape of the microscleres appears to be quite independent 
of their position in the sponge, and must obviously be attributed 
to some specific peculiarity of the ovum from which the sponge 
developed. It is clearly of a blastogenic and not a somatogenic 
character, and it is usually much more remarkable and quite 
as constant as that of the megascleres of the same species. 

The microscleres of the tetraxonid sponges may be divided 
into two categories, termed astrose and sigmatose respectively. 
The former (figs. 14a 14A) may be derived from the tetraxon 
archetype by multiplication of the rays due apparently to 
meristic variation accompanied usually by diminution in size of 



72 the president's address. 

the whqle spicule ; at the same time the rays may become spiny 
or branched in a variety of ways, or even soldered together to 
form a solid siliceous ball (Geodia). 

The sigmatose microscleres are more remarkable and more 
constant in form. They are essentially linear spicules, and 
appear to be derived from minute diactinal oxea. These may be 
straight (" microxea," fig. 15) or bow-shaped (" toxa," figs. 16, 18a, 
186), or their extremities may become bent over to form hooks 
(" sigmata," figs. 17a, 176, 19). A very peculiar modification of 
the sigmata is found in the " diancistra " (fig. 21), which often 
resemble nothing so much as pocket-knives with the blades half 
open. From the sigmata have also doubtless arisen the " chelae," * 
characteristic of the family Desmacidonidae, and, in my opinion, 
the most wonderful of all sponge spicules. Three different chelae 
are shown in figs. 22 24a. 

A typical chela consists of a curved shaft, bearing a number, 
commonly three, of recurved teeth, resembling the flukes of an 
anchor, at each end. The flukes are sometimes expanded into 
thin blades, and so also may be the shaft. Sometimes the flukes 
at the two ends of the spicule are equal in size (" isochelae," 
figs. 22, 22a), sometimes those at one end are larger than those 
at the other (" anisochelae," figs. 23 24a), while in the genus 
Melonanchora a very curious effect is produced by the meeting 
and fusing of opposite flukes of an isochela at the equator of 
the spicule. Minute differences in the form and number of the 
flukes and the shape of the shaft appear to be constant, at any 
rate within the limits of a species ; indeed, the very numerous 
species of Desmacidonidae are to a large extent distinguished from 
one another by these characteristics (compare figs. 23, 23a, and 
24, 24a). 

The same constancy of form is to be observed in the sigmata, 
although here there is less scope for specific differences. In 
both cases the spicule, instead of remaining smooth, may become 
more or less roughened by the development of minute projections. 
This is shown, for example, in the sigmata of the genus Par- 
esperella (fig. 20), where a row of small projections, like the teeth 

* It is perhaps unnecessary to discuss here the evidence for believing 
that the chelae have arisen from sigmata. It is derived partly from the 
development of the chelae themselves and partly from the occurrence of 
intermediate forms. 



THE PRESIDENT'S ADDRESS. 73 

of a saw, occurs at each end of the shaft, just where it bends 
round. 

Now it appears to me quite idle to argue that minute differ- 
ences in the form of the microscleres, such as I have just described, 
are of any importance to the sponge in whose soft tissues these 
microscopic spicules are scattered without order or arrangement. 
Nevertheless they constitute, as I have already said, constant 
specific characters, and have undoubtedly arisen by some process 
of evolution, one form Lading to another just as in the case 
of any other characters. Such characters are, of course, by no 
means confined to sponge spicules ; they may be more or less 
exactly paralleled, for example, in the frustules of Diatoms, the 
shells of Foraminifera and Kadiolaria, and the calcareous spicules 
of Holothurians. Natural selection cannot be directly respon- 
sible for their origin. How, then, are they to be accounted 
for? 

Before attempting to answer this question let us inquire how 
a microsclere actually arises in the sponge. It appears that, 
from an early stage in embryonic development, certain cells, 
known as scleroblasts, or mother-cells, are set aside for the 
purpose of spicule-formation. These mother-cells have the power 
of extracting silica in solution from the sea-water which circu- 
lates through the sponge, and depositing it in the form of solid 
opal, and in the particular shape characteristic of each spicule. 
Each separate microsclere arises thus in the interior of a single 
mother-cell. Let us examine a little more closely the conditions 
under which it is deposited. 

The mother -cell is, of course, a nucleated mass of protoplasm, 
and it appears to be bounded on the outside' by a more or less 
definite cell -membrane. The spicule, at any rate in the case 
of sigmata and chelae, appears to be deposited on the inner 
surface of this membrane, and this fact probably explains why 
it is curved. If we assume, as seems probable, that the mother- 
cell continues to grow while the spicule is being deposited, and 
that the spicule is adherent to the cell-membrane, then we may 
further suppose that the increasing tension and expansion of the 
latter may cause the thin siliceous film to split into flukes or 
teeth. Probably, then, the form of the spicule is largely due to 
mechanical causes. We cannot, however, explain the minute 
details of structure so simply as this, for why should the chela 



74 the president's address. 

of one species have always three flukes and that of another 
always more ? Why should the two ends in some cases be equal 
and in others unequal 1 Why should the teeth at the small end 
sometimes be shaped as in fig. 23 and sometimes as in fig. 24 ? 
and why should some be roughened with spines and others not ? 
We must, I think, assume that these minute differences are 
dependent upon minute differences in the constitution of the 
protoplasm of which the mother-cell is composed. It may be 
a question of the chemical and physical composition of the 
cytoplasm in which the spicule is actually deposited, or it may 
be that the nucleus exerts some direct controlling influence 
upon the form of the spicule, of the nature of which we know 
nothing. 

At any rate we can hardly be wrong in attributing specific 
differences of spicule-form to corresponding differences in the 
constitution of the mother-cells by which they are secreted. The 
remarkable thing is that such differences should be so constant, 
not only throughout hundreds of thousands of mother-cells in 
the same sponge, but throughout the mother-cells of all the 
individuals of the same species. We can only suppose, as I said 
before, that this constancy depends upon some constant peculiarity 
of the germ-plasm from which all the cells of the individual and 
all the individuals of the species originate. Obviously the ferti- 
lised ovum must contain within itself the potentiality of pro- 
ducing, amongst other things, all the different kinds of spicules 
which may happen to characterise the particular species to which 
it belongs. As development goes on differential divisions must 
take place whereby all the different kinds of cells of which the 
adult sponge is composed are segregated, and each mother-cell 
must ultimately retain the power to secrete only one particular 
kind of spicule. Now there is strong reason for believing that 
differential cell-division is effected always by the complex process 
of mitosis or karyokinesis, which concerns chiefly the chromosomes 
of the nucleus, and hence I think we may pretty safely conclude 
that specific differences in the form of the microscleres must 
depend upon differences in the constitution of the nuclei of the 
mother-cells, or, in other words, that the nuclei of the mother- 
cells determine to a large extent the form of the microscleres. 

There appear, in short, to be three secondary factors concerned 
in the production of any particular form of microsclere : (1) the 



THE PRESIDENT'S ADDRESS. 75 

nature of the material (opal) of which the microsclere is com- 
posed ; (2) the nature of the medium in which it is deposited, 
viz. the colloidal cytoplasm of the cell ; and (3) the presence of 
the cell-membrane, by which the growth of the spicule is to some 
extent restrained and guided. All three are, however, doubtless 
dependent upon the hereditary constitution of the mother-cell 
(including, of course, its nucleus), for while the mother-cells in 
siliceous sponges secrete hydrated silica, those of the Calcarea 
secrete carbonate of lime, and so on. 

We have next to inquire how it is that, if the specific forms 
of sponge microscleres are of no importance to the sponge, such 
very remarkable forms should ever have arisen in the course 
of evolution. We have to remember in this connection that we 
are dealing not merely with a few isolated and unrelated forms, 
but with progressive evolutionary series along lines as definite 
as any other lines of evolution with which we are acquainted, 
and which certainly seem to require some directive force to 
explain them. If we were dealing with adaptive characters we 
should at once say that the result was due, as in the case of the 
megascleres, to the natural selection of small, fortuitous, favour- 
able variations ; but the fact that the characters in question are, 
for the most part at any rate, not adaptive, seems, at first sight 
at any rate, to rule natural selection out altogether. 

It might be suggested, however, that the solution of the 
difficulty is to be found in the well-known principle of correlation. 
In accordance with this idea certain characters of an organism 
are inseparably linked together with other characters in such 
a way that any variation in the one must be accompanied by 
a corresponding variation in the other, though the reason why 
such characters should be so linked together is often by no means 
obvious. To upholders of such a view as this the analogy of 
by-products, upon which I laid so much stress at the beginning 
of my address, may, I think, prove useful. Although I doubt 
whether the hypothesis of correlation is adequate to meet the 
present case completely, it certainly seems worth while to 
examine it a little more closely. 

I may illustrate my meaning by reference to the action of a 
few drops of acid upon an alkaline solution of litmus. Two per- 
fectly distinct results will be produced. The solution will become 
acid and it will change from blue to red. You may desire for 



76 the president's address. 

some special purpose to produce one of these results only, but 
they are inseparably connected and you cannot have one without 
the other. You cannot have the result aimed at without having 
also the by-product. 

Now suppose some change in the constitution of the germ- 
plasm of an organism to give rise to two modifications in the 
developing soma or body. We may call the change or modi- 
fication in the germ-plasm GA and the modifications in the soma 
SA and Sa. SA and Sa will be inseparably correlated with one 
another through GA, though as for example in the case of 
white tom-cats with blue eyes, which are said to be generally 
deaf the connection between them may appear to be quite 
arbitrary. 

Suppose further that SA proves to be a useful character and 
Sa a useless one. Then, under the influence of natural selection, 
SA will be preserved and may ultimately develop into a very 
perfect adaptation ; but, if so, GA must also undergo further 
modification, and this modification will likewise affect Set, which will 
therefore keep pace, so to speak, with SA. Thus a non-adaptive 
character (S) may undergo progressive evolution, which, though 
in reality indirectly controlled by the action of natural selection, 
may appear to be guided by some mysterious vital force or 
entelechy. 

Now suppose further that as a result of some change in 
the conditions of life, or merely as the result of its progressive 
evolution in some particular direction, So- in turn acquires some 
value in the struggle for existence. Natural selection will, in 
future, favour its further development directly, and what was 
at first a mere by-product becomes an adaptive character. Thus 
adaptive characters may perhaps become linked together in 
groups, the existence of each group being dependent on some 
particular property of the germ-plasm through which all the 
members of the group are connected. 

At the same time non-aclaptive characters may persist side 
by side with adaptive ones, and even harmful variations may 
persist if their injurious effects are counterbalanced by useful 
characters with which they happen to be correlated and which 
cannot exist without them. Inasmuch, however, as two useful 
characters are more valuable than one, natural selection will 
tend to favour the correlation or linking together of adaptive 



THE PRESIDENT'S ADDRESS. 77 

characters, and this is perhaps the reason why, in the higher 
organisms, non -adaptive characters are less frequently met with 
than in lower forms. Moreover, the effect of natural selection 
will tend to become cumulative and the rate of evolution corres- 
pondingly increased. 

It may be objected that even in the highest organisms 
characters often vary independently of one another, but who 
knows how many characters are really involved in each such 
variation ? Moreover, it by no means follows from what has 
been said above that new characters, whether valuable or 
otherwise, may not arise singly and remain quite independent 
of others. 

In any case the principle of correlation could hardly help us 
to explain the specific forms assumed by sponge microscleres, or 
indeed the exact nature of any non-adaptive character ; it could 
only help to explain why such characters should exist at all and 
why they should undergo progressive evolution. 

If it be asked, what are the adaptive characters with which, 
in our own particular case, the non-adaptive characters of 
the microscleres are supposed to be correlated ? it must be 
admitted that this question cannot at any rate at present be 
answered, but it would be sufficient for the general argument if 
it were granted that a modification in the constitution of the 
germ -plasm which gives rise to a useful character may at the 
same time give rise also to a useless one, or perhaps even to 
many useless ones. 

The question, why are the specific forms of sponge microscleres 
what they are 1 ? is probably one that will have to be answered, 
if it ever is answered, by the chemist and physicist rather than 
by the mere biologist ; or perhaps by that happy combination 
of chemist, physicist and biologist whose advent is so much 
to be desired. I have suggested that the form is probably 
determined by the hereditary constitution of the mother-cell, 
including its power to select silica as the raw material to be 
worked up, but this is no more than to say that the nature of 
the product turned out by a factory depends upon the character 
of the work-people employed and of the machinery and raw 
material with which they have to deal. In the case of our 
microscleres we want to know a great deal more about the 
nature of the machinery and the manner in which it is controlled 



78 the president's address. 

before we can hope to reach even an approximate solution of the 
problem. 

Some light may perhaps be thrown on the subject by ex- 
periments such as those of Leduc and others upon artificial 
osmotic growths. Leduc, in particular, has succeeded in pro- 
ducing very interesting growth-forms by the osmotic action of 
various chemical reagents in solution. Some of these forms bear 
an extraordinary resemblance to the forms of living organisms. 
I do not, of course, attribute much importance to the particular 
forms produced in this manner as explaining the particular 
forms of any living organisms. What they demonstrate is that 
purely chemical and physical causes may give rise to more or less 
definite and at the same time non -crystalline forms in colloidal 
media, and though none of the forms as yet produced come 
anywhere near our sponge-spicules in symmetry or sharpness of 
definition, they certainly seem to indicate a hopeful line of 
inquiry. The particular form produced depends upon the nature 
of the reagents employed and upon the conditions under which 
the experiment is carried out. If these always remain constant 
we may assume that the osmotic growth will always have the same 
form, but probably with the means at our disposal it would be 
impossible to produce exactly the same result twice over. The 
remarkable thing about the sponge microscleres is that within 
the limits of the same species the same results very often are 
exactly reproduced, or at any rate so exactly that we are unable 
to distinguish between them. I suggest that these results are 
produced by chemical and physical causes, involved in and 
controlled by the hereditary constitution of the mother-cell, 
and that any modification of this hereditary constitution must 
give rise to a corresponding modification in the results. Further 
than this I fear we cannot at present venture. 

It has frequently been objected to the theory of natural 
selection that, however much useful characters may be en- 
couraged and fostered in the struggle for existence, it cannot 
account for the first appearance of such characters. This appears 
to me to be a very fair criticism. It seems to me, also, very 
misleading to speak of the origin of species by natural selection, 
for specific characters throughout the animal and vegetable 
kingdom are, I believe, generally non-adaptive, and therefore 
cannot be directly due to natural selection. This is certainly the 



THE PRESIDENT'S ADDRESS. 79 

case with the specific characters of sponges, which, as we have 
seen, depend for the most part upon trivial microscopical differ- 
ences in the shape of the spicules. 

Without entering upon the vexed question of the relation 
between somatogenic and blastogenic characters, we may assume 
in our ignorance that such characters as those which we have 
been discussing arise fortuitously in the germ-plasm, and that 
it is a mere chance whether or not they may prove to be of any 
value to the organism. If they are valuable, natural selection 
will foster and encourage them ; if they are not, they may 
nevertheless persist for many generations unless too injurious to 
their possessors. If linked by correlation with useful characters 
they may be indirectly fostered by natural selection, and un- 
dergo a course of evolution parallel to that of their correlative 
characters. Although they may be useless at first, they may 
acquire some special value under new conditions of life, or in 
the course of their evolution under the old conditions, and then 
natural selection will begin to act upon them directly.* 

Possibly all the characters which an organism exhibits, with 
the important exception of those which are due to the effects 
of use and disuse of organs, or to the response of the 
organism in some other way to the direct action of the environ- 
ment, have first arisen as by-products of the complex chemical 
and physical processes upon which the life of the organism 
depends. 

There is one more aspect of the problem to which I should like 

* Having been asked to give a definite example of a character which, 
at first useless, has ultimately acquired an adaptive value, I suggest the 
pattern of the venation on the front wings, or tegmina, and on the leaf-like 
outgrowths of the abdomen in the leaf-insect Pulchriphyllium cvurifoliuvi. 
This venation so closely resembles that of a leaf as greatly to increase 
the remarkable protective resemblance which undoubtedly enables the 
insect to conceal itself effectively from its enemies. The mere pattern 
of the venation in the more primitive and typical Orthoptera can hardly 
have had any selective value. Of course the venation itself must always 
have been useful, both for supporting the wings and for supplying them with 
air, etc. ; but as regards the pattern which the venation makes (which is 
the character to which I refer) one type of arrangement would seem to 
have been as good as another until it acquired a special adaptive value 
as a factor in bringing about protective resemblance to a leaf, and then 
doubtless the pattern evolved under the influence of natural selection until 
it reached its present degree of perfection. 



80 THE PRESIDENT'S ADDRESS. 

to direct your attention before concluding. The constancy in 
the specific form of the microscleres of the Tetraxonida appears 
to be much greater in the case of the sigmatose than in that of 
the astrose series, and in the former at any rate seems to point 
to the different modifications having arisen as mutations rather 
than as fluctuating variations. This would, I think, be quite 
in harmony with the views which I have been endeavouring to 
express. A mutation, however small it may be, is believed 
to be due to some change, apparently sudden, in the constitution 
of the germ-plasm, which may then remain without further 
alteration until another mutation occurs. To say that the 
change in question is probably of a physico-chemical character 
seems almost a truism ; but if it is so it seems only natural to 
suppose that such a modification, transmitted by cell-division 
to all the mother-cells of a particular kind, may affect in a 
uniform manner the form of all the microscleres deposited in 
these mother-cells, just as a change in the character of the 
reagents employed will affect the form of osmotic growths ex- 
perimentally produced. If this view be correct, we must suppose 
also that any adaptive modifications with which the modifications 
of the microscleres may possibly be correlated must also have 
arisen as mutations. I see no objection to such a supposition, 
for mutations, if they occur sufficiently frequently, may be quite 
as valuable from the point of view of natural selection as small 
fluctuating variations. 

We do not, of course, know what may be the cause of the 
modification in the constitution of the germ-plasm that gives rise 
to a mutation, but there is some reason to believe that it may 
be due either to the permutations and combinations of ancestral 
characters which take place in the maturation and fertilisation 
of the germ-cells, or to the influence of some change of environ- 
ment upon the germ- plasm. If the characters of sponge spicules 
are really of the nature of mutations it should be possible to 
obtain Mendelian results by hybridisation, and I hope that 
at some time in the future experiments may be made with this 
object in view. The difficulties in the way of carrying out 
such experiments would probably, however, be very great, and 
we should require to know a great deal more than we do about 
the breeding habits and life-history of sponges before we could 
hope to bring them to a successful issue. 



33 
33 
33 
3) 
33 
33 
33 



THE PRESIDENT'S ADDRESS. 81 



Description of Plate 7. 

Fig. 1. Ideal primitive tetraxon. 

2. Plagiotriaene of Ecionema carteri, x 52. 

3. Orthotriaene of Pilochrota homelli, X 52. 

4. Anatriaene of Tetilla poculifera, X 52. 
4a. Cladome of 4 x 230. 

5. Protriaene of Tetilla pocidifera, x 52. 
5a. Cladome of 5 x 230. 

6. Dichotriaene of Ecionema laviniensis, x 52. 
6a. Cladome of 6, seen from above, x 52. 
,, la-Id. Ends of triaenes of Stelletta vestigium, with reduced 

cladi, x 230. 
,, 8. End of oxeote of Stelletta vestigium, x 230. 
,, 9. Angulated oxeote of Pachychalina subcylindrica, x 360. 
10. Straight oxeote of Reniera pigmentifera, x 360. 
,, 11. Style of Axinella halichondrioides, x 230. 
12. Tylostyle of Hymedesmia curvistellifera, X 230. 
13. Spined tylostyle of Myxilla tenuissima, x 530. 
,, 14a-14A. Astrose microscleres of Xenospongia patelliformis, 

X 530. 
15. Microxeote microsclere of Desmacella tubidata, x 230. 
16. Toxiform microsclere of Gellius angulatus var. canalicu- 

lata, x 230. 
17a, lib. Sigmata of Gellius angulatus var. canalicidata, x 230. 

(Note the angulation of the spicule, suggesting 

derivation from a diactinal microxeote, such as is 

represented in figs. 26a-26c.) 
18a, 186. Toxa of Toxochalina robusta var. ridleyi, X 230. 

19. Sigma of Desmacidon reptans, X 512. 

20. End of sigma of Paresperella serratohamata, x 530. 

21. Diancistron of Vomerula or Hamacantha, x about 200. 

22. Isochela of Esperiopsis pulchella, front view, x 284. 
,, 22a. Side view of same, x 284. 

23. Anisochela of Cladorhiza jientacrinus, front view, x 700. 
,, 23a. Side view of same, x 700. 
24. Anisochela of Cladorhiza (?) tridentata, front view, 

x 360. 
24a. Side view of same, x 360. 
Journ. Q. M. C, Series II. No 72 6 



35 
33 
33 
J3 



82 the president's address. 

Fig. 25. Primitive tetraxon (calthrops) of Dercitopsis ceylonica, 
x 230. 
26a-26c. Small oxea of Dercitopsis ceylonica, x 230. (Oxea 
four or five times as large occur in the same 
sponge.) 

(Figs. 2-186, 20, 25-26c, from Dendy's Report on the Sponges 
collected by Prof. Herdman at Ceylon in 1902. Figs. 19, 21, 22, 
22a, 24, 24a, from Ridley and Dendy's Report on the Challertgo 
Monaxonida. Figs. 23, 23a, from Dendy in Ann. <& Mag. Nat. 
Hist., Ser. 5, vol. 20, PI. xv.) 



Journ. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 72, April 1913. 



Journ.dM.C 



Ser.2yol.XlI 




Spicules of Tetra-xorud Sponges. 



83 



ON FIVE NEW SPECIES OF BDELLOID ROTIFERA. 

By David Bryce. 

{Read March 2oth, 1913.) 

Plates 8 & 9. 

The five species of which descriptions are furnished in the present 
paper have been known as distinct forms for many years past, 
although their distinguishing characteristics have not hitherto 
been gathered into the formal diagnosis which constitutes scientific 
baptism. Four of them belong to that important section of the 
Philodinidae in which the food is formed into pellets after passing 
through the mastax, and are assigned to the genus Habrotrocha. 
The fifth species belongs to the more numerous section of the 
same family in which the food is not at any time agglutinated 
into pellets, and being oviparous and possessed of three toes is a 
member of the genus Callidina, as now restricted. 

Under the name of Habrotrocha munda, I describe the form to 
which T referred in some remarks upon the identity of Callidina 
elegans Ehrbg., appended to my paper on " A New Classification 
of the Bdelloid Rotifera," * as having been wrongly identified as 
that species by Hudson and Gosse and by other writers. I have 
endeavoured in that place to show as clearly as possible my 
reasons for the belief that this form cannot be that which Ehren- 
berg described ; and inasmuch as none of the various correspondents 
who have addressed me with regard to my classification have 
advanced a view contrary to my own in this matter, I think 
that this victim of mistaken identity may now be established on 
a firmer and less assailable basis. 

This species is the most common of the few pellet-making forms 
which have their usual habitat in ponds and ditches. In fresh 
gatherings it may frequently be seen swimming vigorously with 
its head slightly deflexed, or perhaps marching about at a great 

* Jaimi. Q. M. C, Ser. 2, Vol. XI., p. 61. 



84 D. BRYCE ON FIVE NEW SPECIES OF BDELLOID ROTIFERA. 

pace, and will often attract attention from the bright reddish 
colour of the stomach wall. On closer examination it may be 
readily recognised from the peculiar shape and pose of the spurs, 
which are quite distinctive, and from the many-toothed rami. 
Under more natural conditions, it takes shelter in any convenient 
recess among debris or in leaf axils, and there makes its home, 
protruding the head and neck when it desires to feed. 

The second species, Habrotrocha torquata, has similar many- 
toothed rami, but in several other respects differs distinctly from 
H. munda. I believe that in some quarters it has also been 
accepted as Callidina elegans Ehrbg., probably on account of the 
rami. Unlike H. munda, it is never found in ditches or ponds, 
but has its habitat usually in mosses growing in positions fre- 
quently wet. The spurs are of simple form and the stomach wall 
is never of reddish tint. It has not been observed to seclude itself 
in any way and is of comparatively quiet habit. Its specific 
name was suggested by a curious but illusory appearance in some 
positions of an annulus encircling the expanded corona. 

The third of the pellet-making species, Habrotrocha spicida, is a " 
rather smaller form, which has the, so far, unique distinction of a 
single spine of small size placed on the pre-anal segment on the 
median dorsal line. When the body is contracted, or when the 
animal is seen in lateral view, this spine is sufficiently obvious, 
but at other times it is most easily overlooked. In my own 
experience this Bdelloid has only occurred in hilly country in 
elevated positions, but I learn from Mr. James Murray that he 
has also met with it in lowland habitats. 

The fourth species, Habrotrocha ligida, is one of those puzzling 
forms which can only be recognised with certainty when it is feed- 
ing. It is mainly distinguished by the possession of a small fleshy 
tooth, which stands erect in front of the narrow sulcus between the 
two pedicels of the corona, difficult to discern except in direct dorsal 
view. In other respects it offers little to remark. 

For my earliest knowledge of the new Callidina, I am indebted 
to my esteemed correspondent the late Forstmeister L. Bilfinger, 



D. BRYCE ON FIVE NEW SPECIES OF BDELLOID ROTIFERA. 85 

of Stuttgart, who sent to me, as long ago as 1894, a sketch of the 
animal together with some moss in which it occurred. I have 
therefore given it the specific name Bilfingeri, in honour and in 
grateful appreciation of a most courteous correspondent and of a 
painstaking and careful observer of the Rotifera. The type form 
of this species is marked by a series of lateral and dorsal knob- 
like prominences on the posterior half of the trunk. As in most 
other species with such knobs or with spines, the presence of these 
ornaments is not constant, and occasional examples are found in 
which some or even all the typical prominences are absent. 

Habrotrocha munda sp. no v. (PI. 8, fig. 1). 

Specific Characters. Corona moderately wide, exceeding collar ; 
pedicels with dorsal inclination ; discs more strongly inclined in 
same direction. Under lip relatively high, centrally prominent 
and spoutlike, Dorsal antenna long. Rami with seven or 
more fine teeth. First foot joint with dorsal prominence. Spurs 
resembling caudal processes of Chaetonotus. 

In general build and in the somewhat " smothered " appearance 
of the corona, due in this case to the shortness of the pedicels and 
to the very oblique setting upon them of the trochal discs, this 
species has a certain resemblance to Habrotrocha torquata, but 
can usually be distinguished from it by the shape of the spurs, 
which in typical specimens have a very characteristic moulding 
and pose. In the normal or extended position, the body is spindle- 
shaped, distinctly larger about or a little behind the centre, and 
smaller at either extremity, and rarely exceeds 320 /x in length. 
While the rostrum is shorter and thicker than usual, the head 
and neck are only moderately stout, the trunk being distinctly 
larger (sometimes almost swollen when well fed), the lumbar 
segments short and tapering rapidly to a relatively small and 
slender foot of (I think) three segments. When creeping, the 
dorsal and lateral longitudinal skin-folds are usually well marked. 
In adult examples the stomach wall is frequently of a vivid 
reddish colour, and the lumen of the stomach is usually crammed 



86 D. BRYCE ON FIVE NEW SPECIES OF BDELLOID ROTIFERA. 

with obvious food pellets. The first foot segment has a median 
dorsal prominence of moderate height, rather wider than long, 
and best seen in lateral view. The second segment has the very- 
characteristic spurs, which always suggest to me the caudal 
processes of the common form of Chaetonotus. They are longer 
than is customary among pellet-making species, frequently 
measuring 14 to 15 /x in length, but are sometimes much shorter. 
Near the base they are swollen on the inner side, and closely 
approximate. About mid-length they suddenly diminish in 
thickness and are thence produced to rather acute points. The 
outer side of each is nearly straight, and they are held at a 
slightly divergent angle. The three toes are difficult to see, but 
the terminal pair (and I think the dorsal toe" as well) are 
moderately long and acute. The dorsal antenna is sometimes 
quite 25 fx long and is carried much as in Rotifer macroceros t 
being inclined backwards when the animal is creeping about, and 
directed more or less forward when it is feeding. 

The corona attains a width of about 45 li. The trochal discs 
are separated by a shallow furrow, which narrows to a mere 
notch as it nears the ventral side. On that side accordingly the 
principal wreath is almost uninterrupted, and in place of the 
customary appearance in front view of two distinct " wheels '' 
there is rather that of a toothed band passing rapidly round a. 
single transversely elliptic course, distinctly broken on the dorsal 
side and only slightly indented on the ventral. In lateral view 
it is seen that the pedicels are dorsally inclined, short and 
obliquely truncate, so that the trochal discs are still more inclined 
towards the dorsal side. The under lip and mouth margins are 
high in relation to the discs, and the former centrally prominent 
and spout-like as in Habrotrocha angusticollis, but in a lesser 
degree. The upper lip is usually hidden by the reverted rostrum. 
So far as I have been able to discern, it rises moderately towards 
the centre and is neither bilobed nor reflexed. The rami are 
about 19 fx in length, somewhat triangular in outline, and have 
each at least seven very fine teeth. 



D. BRYCE ON FIVE NEW SPECIES OF BDELLOID ROTIFERA. 87 

Habrotrocha munda occurs most frequently in pools, especially 
when water-mosses and anacharis are present. I have also found 
it occasionally in sphagnum and in confervae, both in floating 
masses and in the growth upon submerged stones. In suitable 
situations it makes for itself a rough case or nest of the same type 
as that produced by Rotifer macroceros. 

It is of cosmopolitan distribution. I have noted it for 
England, Scotland, Germany (Baden, Black Forest, Wurtemberg, 
Stuttgart), Cape Colony. 

Habrotrocha torquata sp. nov. (PL 8, fig. 2). 

Specific Characters. Of medium size and stoutness. Corona 
equal to or rather exceeding collar ; pedicels short, distinct ; 
trochal discs more or less dorsally inclined. Upper lip moderately 
high, undivided but centrally slightly reflexed ; under lip 
unusually high, yet scarcely prominent. Dorsal antenna rather 
long. Kami with six or more fine teeth. Spurs short, divergent, 
conical. 

When creeping about, H. torquata is somewhat difficult to 
recognise, as it lacks any conspicuous peculiarities of form, colour 
or size. It is perhaps most usefully described by comparison with 
other species of the same genus having similar many-toothed 
rami. The body is of moderate dimensions, less spindle-shaped 
than in H. munda, but less parallel-sided than in H. elegans 
(Milne). The rather short foot is longer and more distinct than 
in the latter species, but is less so than in H. constricta (Duj.). 
The spurs are simple short cones of moderate stoutness, and are 
held at almost a right angle, differing thus from the slighter and 
widely divergent spurs of H. constricta, the short, peg-like, very 
slightly divergent spurs of H. elegans (Milne) and the com- 
paratively long moulded spurs of H. munda. In most examples 
the stomach is not obviously tinted, but is occasionally of a 
yellowish colour, yet never of the reddish shade frequent in 
H. munda, H. auricidata, and other species. 

In habit it resembles H. constricta ; that is to say, it lives in the 



88 D. BRYCE ON FIVE NEW SPECIES OF BDELLOID ROTIFERA. 

open and is not a dweller in the shelter afforded by natural or 
contrived gatherings of dirt particles or debris like H. elegans 
(Milne) and H. munda. I have never met with it in pools, but 
usually in mosses (not sphagnum) growing in wet positions. 
When the corona is displayed, it is seen to have a quite unusual 
appearance. As in H. munda, the trochal discs are inclined 
towards the dorsal side, but in a varying degree, and are 
separated by a furrow deeper than in that species. The upper 
lip rises in a broad rounded lobe which is centrally bent back, 
leaving visible the fleshy connection, or nexus, between the short 
pedicels. On the ventral side the under lip rises unusually high, 
and thus in dorsal view, the collar, which passes round the 
pedicels on either side and merges gradually into the under lip, 
has an obliquely upward direction, not obliquely downward as 
customary. This results in the optical presentments of the 
rapidly beating cilia of the secondary wreath (those lining the 
collar and passing round to the mouth), and of the cilia of the 
principal wreath (those of the trochal discs), being to some extent 
commingled, and there is the appearance of an annulus or ring 
passing round the trochal discs immediately below their margins. 
When the discs are seen so that their planes are nearly 
coincident with the line of sight, they appear to have deeply 
grooved margins, but the exact appearance varies with the angle 
at which they are viewed. Whether the appearance be that of a 
ring or of discs with deeply grooved margins, it is in my opinion 
purely an optical effect arising from the mutual interference of 
the light rays from the two wreaths of cilia. 

The high under lip is unusually flat and inconspicuous ; the 
lateral margins of the mouth are scarcely thickened and the 
mouth cavity is small as compared with that of other Philo- 
dinidae. When feeding the lumbar plicae are well marked. 

The foot represents about one-ninth of the total length. It 
has four joints, the first having dorsally a distinct thickening of 
the hypodermis. 

In the confinement of a small cell H. torquata proved only 



D. BRYCE ON FIVE NEW SPECIES OF BDELLOID ROTIFERA. 89 

moderately hardy. After a few days, most specimens would 
feed freely under the unaccustomed light and would remain 
quiet, but I have never known eggs to be laid under such 
conditions. 

By no means a common species, yet widely distributed ; I noted 
it first in moss sent me in 1895 by Forstmeister L. Bilfinger, 
of Stuttgart. I have since found it in moss from Epping Forest, 
Essex ; Chagford, Devon ; Pass of Leny, Perthshire ; Black 
Forest, Baden. 

Dimensions. Greatest length 410 fx, more frequently 320 to 
350 fx. Corona 38 to 41 /x. Kami about 15 fx. Spurs 6 to 9 /x. 

Habrotrocha spicula sp. nov. (PI. 9, fig. 1). 

Specific Characters. A single, short, blunt spine, sub-erect 
upon dorsal median line of pre-anal segment. Corona small, 
13-18 [x wide; pedicels adnate; upper lip high, rounded, un- 
divided. Rami with four teeth each. Spurs, short cones, widely 
separated. 

A rather small species, chiefly noteworthy for the solitary 
spine and its unusual position. No other Bdelloid yet known 
has only a single spine or has spines only upon the pre-anal 
segment as in this case. When the animal is in its most 
retracted position, as one usually sees it lying inert among moss 
debris, the spine stands out distinctly at the hinder end of the 
body, and it is also well shown when the animal is feeding and 
assumes the squatting position natural to many species. It is 
easily overlooked when the animal is crawling about unless a 
good side-view is presented. It springs from a thickened base, 
and is rather blunt, short and slightly bent. 

When seen from the front the very small corona is nearly 
circular in outline, the trochal discs being separated by a shallow 
furrow and the pedicels adnate. In dorsal view the high 
rounded upper lip rises quite to the level of the trochal discs, 
and its apex indeed is visible in ventral view. The margins of the 
mouth have small angular lateral prominences, which are partly 



90 D. BRYCE ON FIVE NEW SPECIES OF BDELLOID ROTIFERA. 

visible even from the dorsal side and add to the apparent width 
of the collar. 

When extended the body is moderately stout and the longi- 
tudinal skin-folds are well marked. In most cases it is colourless, 
but examples of a faintly reddish colour have been seen. The 
antenna is short, but rather stout. The rami are small, 14-15 tt 
long. 

The foot tapers rapidly and is very short. In the feeding 
position it is usually hidden beneath the trunk. It seems un- 
suited for crawling on a smooth surface such as glass, as the 
animals have unusual difficulty in getting foothold. The first 
joint has frequently a strong protuberance on its dorsal side. 
The spurs are very small cones about 3 /x long separated by an 
interspace about 6 /x wide. 

The largest examples measured were about 200 jx long when 
extended, but others were from 170 to 185 /x. My earliest speci- 
mens were found in mosses collected for me on Cader Idris by 
Mr. D. J. Scourfield in 1895. Others came from collections on 
Mickle Fell and on Snowdon by the same friend. In 1898 
I found it in moss from the top of Ben Ledi, in 1907 from the 
top of Ben Vrackie, both in Perthshire ; and in 1906 from tree- 
moss in the woods above Triberg in the Black Forest, Baden. It 
has also been found repeatedly by Mr. James Murray in Scotland 
and in many foreign habitats. 

Distribution : cosmopolitan, mostly at high elevations. 
Habitat : ground, rock or tree-mosses. 

Habrotrocha ligula sp. nov. (PI. 9, fig. 2). 

Specific Characters. Moderately slender. Corona somewhat 
wider than collar ; pedicels rather high, semi-adnate ; discs 
separated by narrow sulcus. Upper lip rising very slightly and 
displaying a small fleshy tooth, which near its apex tapers 
suddenly to a point. Rami with four teeth each. Foot three- 
jointed ; spurs small, tapering cones with interspace nearly equal 
to their length. 



D. BRYCE ON FIVE NEW SPECIES OF BDELLOID ROTIFERA. 91 

A species of rather less than medium size which in its extended 
position offers no obvious character for its recognition. The 
rostrum is short and stout, and the dorsal surface has a distinct 
almost ridge-like thickening of the hypodermis, best seen in 
lateral view. Its movements are active when crawling about, 
and when feeding it sways and bends almost incessantly in all 
directions, the body being well extended and the upper foot 
joints visible. The trochal discs are rather small and the 
greatest width of the corona little exceeds that of the collar. The 
pedicels are adnate to nearly half their height and are very 
slightly divergent. At the dorsal end of the nexus between 
them is a small fleshy ligule or tooth, which for the most part is 
nearly cylindrical, but near the tip tapers rather suddenly to a 
point. It is so inconspicuous that it can rarely be seen except 
in direct dorsal view and when the animal keeps steady for a 
brief interval. Even then the exact shape of the ligule is 
difficult to determine, but I think that it differs somewhat from 
the type of ligule possessed by any of the few Bdelloids in which 
this peculiar ornament or organ has been seen. In Habrotrocha 
eremita (Bryce), in which it was first noted, it is a simple, short, 
peg-like tooth, very slender and tapering gradually, and, to judge 
from the figures given by Murray, it appears to be of the same 
character in Habrotrocha acornis Murray and Callidina lepida 
Murray. In the present species the appearance is rather that 
of a fleshy cylindrical pedestal, with a tapering point inset at 
the end of the pedestal as if in a socket. 

The upper lip rises in a low curve about as high as the base 
of the ligule. The rami have four teeth, but one tooth on each 
is much less prominent than the others. I have noticed that 
the food pellets are rather small. Examples isolated produced 
eggs of oval outline, hyaline, smooth-shelled, measuring 70 /x at 
the longest by 43 //, at the shortest diameter. 

I had this species first in 1894 from a roadside near Deal, and 
in the following year from a wall in Bognor ; in both cases from 
small button-like tufts of w T all-moss. I did not see it again until 



92 D. BRYCE ON FIVE NEW SPECIES OF BDELLOID ROTIFERA. 

some few weeks ago, when it was brought to me by Mr. G. K. 
Dunstall, who had obtained it from moss collected near Leith 
Hill, in Surrey. It is probably a more common species than 
these three isolated records would indicate. It may be that it 
has a partiality for small tufts of moss (which do not invite 
examination), or perhaps its restlessness and the absence of any 
very obvious peculiarity when marching about has led to its 
being overlooked. 

In view of Murray's opinion that the presence of a ligule in 
Bdelloids is an unsafe specific character, as it often appears in 
species where it is not normally present, it must be pointed out 
that, while it may be presumed that the ligule in Habrotrocha 
ligula is fairly constant, it is by no means impossible that 
examples should occur in which it might be absent, and in that 
case, if normal specimens were not available for comparison, 
identification might well be difficult. 

Dimensions. Length about 320 fx. Corona 30 /x. Collar 25 /a. 
Ramus 1 7 /x. Spurs 5 ll. 



Callidina Bilfingeri sp. nov. (PI. 9, fig. 3). 

Specific Characters. Of medium size, and moderately stout, 
posterior trunk having a series of knob-like prominences. 
Trochal discs well separated, but corona not exceeding collar 
width. Upper lip rather high and wide, with shallow central 
depression. Rami with two teeth each. Dorsal antenna short, 
about half the neck thickness. Foot three- jointed; first joint 
laterally swollen, second very short, somewhat distended to form 
sucker-like disc. Spurs very minute cones, with wide, slightly 
convex interspace. 

So far as I am aware, this rather well-marked species, of 
moderately stout build and medium size, has been met with only 
in ground-mosses. Typical specimens are easily recognised from 
the series of knob-like prominences which ornament the sides of 
the trunk segments and the dorsal surface of the rump segments. 



D. BRYCE ON FIVE NEW SPECIES OF BDELLOID R0TIFER4. 93 

The number of these "knobs" appears to be very inconstant, 
as in sketches made by Forstmeister Bil finger, James Murray, 
and myself it varies from eleven to five ; and I was informed 
by the first-named correspondent that he had met with examples 
without any knobs at all. In such cases the species can still be 
determined with moderate certainty from the peculiar structure 
of the second foot joint, and the minuteness and wide separation 
of the spurs. When the full number of prominences are present 
they are distributed thus : the third segment of the trunk (or 
central portion of the body) has one at either side, close to its 
anterior boundary ; the same segment and the fourth and the 
sixth have each one at either side near their posterior boundaries; 
while on the dorsal side of the fifth and sixth segments there are 
three more, arranged in a triangle (two in front on the fifth 
and one behind on the sixth segment, the latter on the median 
line). The fifth segment is moderately swollen laterally. The 
lateral knobs on the sixth segment (the anal) are more nearly 
constant than the others. Those most frequently absent are 
the anterior pair of the third segment. 

The first foot joint has distinct lateral swellings, and is per- 
haps swollen dorsally as well. The second joint is very short, 
and slightly distended with thickened skin, forming a sucker- 
like disc from the lower surface of which the three short, broad 
toes are protrusible. The flange-like hinder margin of this 
foot disc forms the slightly convex interspace between two very 
minute spurs. 

When creeping about the animal is seen to have a short and 
stout rostrum. In the feeding position the body is somewhat 
flattened, and the dorsal longitudinal skin-folds are obliterated. 
The trochal discs are well separated, but the head is stout and 
the corona does not exceed the collar width. The upper lip rises 
rather widely and high, and has a shallow central depression. 
The rami are 14 to 16 ^t long, and are widest above the middle. 
The anterior outer margin of each is distinctly thickened, and 
passes gradually into a delicate winglike expansion of the ramus. 



94 D. BRYCE ON FIVE NEW SPECIES OF BDELLOID ROTIFERA. 

As already stated, this species was first discovered by the 
late Forstmeister L. Bilfinger in the vicinity of Stuttgart, and 
notified to me in 1894. It was afterwards found by Mr. George 
Western, probably near London, and in 1904 by James Murray, 
near Fort Augustus. In 1906 I met with it in moss gathered 
on the bank -of a roadside ditch near Triberg, in the Black 
Forest. Quite recently numerous examples have been found in 
moss collected by Mr. G. K. Dunstall near Leith Hill, Surrey. 

Dimensions. Length about 315 /a. Corona 38 /x. Collar 41 /a. 

Spurs 1 to 2 /a (on inner edge). 
i 

Description of Plates 8 and 9. 

Plate 8. 

Fig. 1. Habrotrocha munda sp. nov., extended, dorsal view, x 350 ; 

la, head and neck, corona displayed, in lateral view, 

X 650 ; lb, the same, in ventral view, x 750 ; lc, 

mouth, in front view (diagrammatic). 

2. Habrotrocha torquata sp. nov. In feeding position, corona 

displayed, dorsal view, x 550 ; 2a, spurs, x 1600. 

Plate 9. 

Fig. 1. Habrotroclut spicula sp. nov. In feeding position, corona 
displayed, ventral view, x 600 ; la, retracted position, 
X 600 ; 16, foot extended, dorsal view, x 800 ; lc, ramus, 
X1600. 

,, 2. Habrotrocha ligula sp. nov. In feeding position, corona 
displayed, dorsal view, x 480. 

,, 3. Callidina Bilfingeri sp. nov. In feeding position, dorsal 
view, x 350; 3a, ramus, x 1600. 



Journ. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 72, April 1913. 



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95 



NOTES. 

A NEW LOW-POWER CONDENSER 

By Edward M. Nelson, F.R.M.S. 

{Read November 26th, 1912.) 

The condensers which at present are supplied with microscopes 
are only suitable for low powers ranging from | inch upwards. 
With powers lower than these a difficulty arises, for it is not 
possible to fill the field with the image of the source of light 
focused upon the object, as it should be. Substage condensers 
suitable for low powers are all too short in focus, consequently 
the image of the source of light is far too small. 

In these circumstances microscopists have been, and are, 
accustomed to waive critical illumination and employ the most 
uncritical of all illumination, viz. to focus the image of the 
source of light upon the front lens of the objective ; this is 
nothing more nor less than lantern illumination, which gives 
a critical image of a diaphragm limiting the field, but of nothing 
else ; all delicate lines and structures are coated with black 
diffraction borders. 

The obstacle in the way of using a long-focus condenser is that 
there is not sufficient room to focus it. 

Powell's No. 1 stand has a good deal of room, but not enough, 
and other microscopes are simply nowhere. Now the way this 
difficulty may be surmounted is to construct the condenser upon 
the telephoto principle. This has now been done, and Messrs. 
Baker will show you this evening a substage condenser they have 
made from my design which has 4 inches of focal length and 
requires only 1 inch of working distance. With this condenser 
the image of the fiat of the flame bears the same relation to a 
4-inch objective with the large field of a P. & L. No. 1 A eye- 
piece, as the image with one of the ordinary universal condensers, 
with the top off, does to a | inch ; and this is precisely what 
was wanted. 

Now let us understand exactly what this means. A 4-inch 
objective has a focal length of 2| inches; with a No. 1 A 
eyepiece the size of the object on the stage that is embraced 



96 E. M. NELSON ON MICROSCOPE CONSTRUCTION 

in a field of view is $ inch, therefore it is necessary for the 
condenser to focus upon the stage an image of the flat of the 
flame $ of an inch wide. 

The condenser has a low aperture of N.A. 0*14, but large enough 
for the objectives for which it is intended to be used. 



NAVICULA RHOMBOIDES AND ALLIED FORMS.* 

(Addendum.) 

By Edward M. Nelson, F.R.M.S. 
{Bead November 2M7i, 1912.) 

With reference to the question, " What was the Amician Test?" 
quite accidentally I recently came across a notice to the effect 
that the test used by the Jurors at the International Exhibition 
(London, 1862) was the Navicula ?'homboides under the name of 
JV. affinis. This of course clears up all the difficulty. This 
N. rhomboides would have been of the kind termed the 
" English " rhomboides in my paper, and would have had 72 to 
73 striae in 0*001 inch. 

ON MICROSCOPE CONSTRUCTION AND THE SIDE 
SCREW FINE ADJUSTMENT. 

By Edward M. Nelson, F.R.M.S. 

(Bead November 26th, 1912.) 

There is one point which has been overlooked with respect to 
the evolution of the microscope. It is thought that the modern 
plan of placing the coarse adjustment slide and the body upon the 
fine adjustment was the invention of Zentmayer (1876), and that 
it first appeared in this country in the Ross-Zen t may er model. 
This however is not the case, for Powell in 1841 invented this 
plan, as well as that of the side pinion fine adjustment, now so 
much in vogue. 

In the frontispiece of Cooper's Microscopiccd Joumcd an illus- 
tration of this model will be found, f Some years ago Mr. T. 

* Journal Q.M.C., Ser. 2. vol. ii. p. 93. 

f This was the first microscope Powell introduced after Lealand had 
joined the firm (vide Journal B.M.S., 1900, p. 287, fig. 78). 



AND THE SIDE SCREW FINE ADJUSTMENT. 97 

Powell kindly showed me one of these microscopes, but it had 
escaped my memory. The coarse adjustment was by rack and 
pinion ; this was not attached to the limb by a slide, but by a 
kind of cradle. This cradle was pressed down by a spring on 
to a horizontal cone, which was moved by a horizontal fine- 
adjustment screw, which had a milled head on each side of the 
limb. 

The importance of this model should be recognised by every one 
who uses a microscope, for not only was it the first microscope 
to have a side screw, but also it was the first instrument in 
which we find the limb attached to the foot on two upright 
pillars. This double support to the joint (now almost universally 
used) was the invention of George Jackson (President R.M.S. 
1852-3). Before this all microscopes that were capable of being 
inclined were attached to the foot by a single upright post and a 
compass joint.* Powell attached the two pillars to a flat tripod 
base by a swivel so that the base could be placed in such a 
position as to give the greatest amount of stability however 
much the body might be inclined (some makers in copying this 
arrangement graduated this arc of rotation !). 

Ross copied this kind of joint in the model he brought out in 
1843, but substituted two parallel flat plates for the two pillars ; 
but Messrs. Smith and Beck adopted the two-pillar form in their 
1846 model. 

This microscope of Powell's had a Turrell stage, a micrometer 
stage, an achromatic condenser, Nicol polarising and analysing 
prisms ; so it was in its day an instrument of a very advanced 
type. In 1843 Powell & Lealand discarded the two pillars for 
the gipsy tripod, which is the best form of foot ever designed.f 

Coming now to modern times, horizontal fine adjustments may 
be placed in two groups, viz. (a) those with continuous motion 
and (b) those without. The drawback which those of the first 
kind possess is that the user does not know whether he is 
focusing up or down ; and the drawback which all the second 
kind, excepting the Berger, have is that of damage and injury to 
the delicate moving parts when they butt up against a stop. 
The Berger avoids all risk of damage from this source by causing 

* Some ancient non-achromatic microscopes had ball and socket joints, 
but those early forms are not now under discussion, 
t For fig. see Journal R.M.S., 1900, p. 289, fig. 79 
Journ. Q. M. C, Series II. No. 72 7 



98 



E. M. NELSON ON MICROSCOPE CONSTRUCTION. 



an idle nut to butt against a stop ; if this nut receives damage or- 
strain to its thread it is of no importance. The first kind adopt 
a continuous motion in order to secure immunity from this 
danger, and put up with the great disadvantage of having a fine 
adjustment which does not follow the direction of the movement 
of the milled head. 

The following simple device has been designed to effectually 
prevent any damage taking place. To the right hand side of the 
limb, where the micrometer drum-head is placed, a short piece of 
tube, threaded on the outside, is fixed, and through it the fine 
adjustment pinion passes just like the cannon pinion in a clock. 





Fig. 1. 



Fig. 2. 



An idle nut works on this screw in a slot inside the micrometer 
drum. It is then arranged that this nut will permit ten rotations 
of the fine-adjustment pinion to be made, and then stop further 
motion by butting either against the side of the limb or against 
the end of the inside of the micrometer drum. Figs. 1 and 2 will 
make this simple device clear without further explanation. 



NOTE ON PLEUROSIGMA ANGULATUM. 

By Edward M. Nelson, F.R.M.S. 

{Read January 28th, 1913.) 

About the end of the eighties I took a photomicrograph of a 
specimen of Pleurosigma angulation, which had been broken in 
a very remarkable manner so that it was possible to demon- 



E. M. NELSON ON V LEU RO SIGMA AStiULATUM. 99 

strate the existence of two membranes. At one part the upper 
membrane had been torn away leaving the lower membrane, 
at another the lower membrane had gone while the upper was 
left, the rest of the valve having both membranes in position. 
These three photomicrographs of the upper, lower and both 
membranes were exhibited to the Club. No other specimen I 
have seen has been so fortunately fractured as to demonstrate 
both membranes so clearly as this one. 

The network in one membrane differs slightly from that of 
the other, so that after a little practice one is able to state 
whether the membrane under observation is an upper or lower 
membrane. The upper membrane in P. strigosum resembles 
the diamond panes of a leaded light, while the lower is like 
wire netting, fig. 3. In P. balticum and allied forms the upper 
memb^ine has slit-like apertures in longitudinal rows, while 

III 



O-go 

Fig. 3. Fig. 4. 

the lower membrane has circular apertures, fig. 4, where the 
circular apertures in the lower membrane are seen through 
the intercostal silex of the upper membrane and in a line with 
the bars between the slits. 

Now at that time it was thought, and probably it is still 
the received opinion, that the lower membrane " eye-spotted " 
the upper membrane ; by which is meant that the apertures 
in the lower membrane are directly below those in the upper 
membrane much in the same way as in Coscinodiscus the eye- 
spot is directly below the perforated cap at the top of the cell. 

Recently, however, study on P. angidatum with a Leitz apo- 
chromat, y 1 ^ inch of 1*40 N.A., has caused me to change my 
opinion, for the apertures in the lower membrane can be un- 
mistakably seen below the intercostals of the upper membrane, 
and this is true not only of P. angidatum, but also of all allied 
forms that have been examined. 

No mention has been made of Mr. T. F. Smith's observation. 



100 E. M. NELSON ON PLEUROSIGMA ANGULATUM. 

on the structure of the genus Pleurosigma, because this note, 
not being an exposition of the structure of this genus, deals 
merely with the single fact of my altered opinion with regard 
to the apertures in the lower membrane not " eye-spotting " 
those in the upper. 

The genus Pleurosigma has been seventy years before the 
microscopical world, not laid aside, but worked at continuously 
by the most skilful microscopists, yet all the problems con- 
nected with their structure have not been solved. It is only 
by recording from time to time a little bit here and a little 
bit there, and by putting these little bits together, that complete 
and accurate knowledge of this difficult subject will be attained. 

ACTINOCYCLUS RALFSII AND A COLOURED COMA. 

By E. M. Nelson, F.R.M.S. 
{Read January 28th, 1913.) 

The following account of a microscopical phenomenon, never 
previously observed, may be of interest. 

When working on a mixed diatom gathering, dry and un- 
covered, with a Powell & Lealand | inch and a lieberkuhn, there 
appeared round an Actinocyclus Ralfsii a wide border of brilliant 
orange, green and blue light. The inside of the valve was 
uppermost and the bottom of the cup was in focus, so that the 
surrounding mist was caused by the out-of -focus edge, which, of 
course, was at a higher level. Any one seeing this coloured mist 
would have exclaimed what a badly corrected objective ! but if 
they had looked at the other diatoms in the field, they would 
have seen that the out-of -focus coma was white ! The colour, 
then, must be a function of the Actinocyclus. Another objective 
with a lieberkuhn, viz. a Powell & Lealand T 4 ^ inch, was tried on 
the same diatom ; the border was now red, the green and blue 
having gone ! A third objective, viz. a Wenham | inch with 
lieberkuhn (really a T 4 <y inch), and the image seen had no colour ! 

Here, then, we have an example of an object affecting different 
objectives differently. Would some of our " brass and glass " 
experts kindly take this matter up ? 

Joara. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 72, April 1913. 



101 



NOTICES OF BOOKS. 

Problems of Life and Reproduction. By Marcus Hartog, 
M.A., D.Sc., F.L.S. 8 x 5J in. ; xx -f 362 pages ; one 
plate, 41 figures in the text, and three diagrams. London : 
John Murray, 1912. Price 7s. 6d. net. 

In taking up this book one cannot avoid a feeling of regret 
that the author was unable to carry out his original intention of 
writing a general treatise on Reproduction suited to the layman 
interested in biological questions. By his researches the author 
would have been well fitted for such a task. As it is, the book 
consists of a series of papers on debatable subjects in Biology 
gathered from various scientific journals and reviews, and ranging 
in date from 1892 to 1910. They have been revised in part in 
the light of more recent research, and brought up to date. 

There is much to interest the microscopist, and to one who is 
not already acquainted with them in their original form they may 
be recommended. The earlier papers deal with the problems 
of reproduction as presented in the Protista conjugation and 
rejuvenescence and the beginnings of sexual reproduction or 
syngamy. The paper on Fertilisation contains a large number 
of interesting facts gathered together ; here the author puts 
forward the idea that it is the linin and not the chromatin 
(which only serves a purely mechanical function) which is the 
real transmitter of inherited properties. This idea is more 
fully developed in Chapter 1Y. on " Mitokinetism " a new 
force which the author brings to our aid in explaining the 
mechanics of the mitotic process of nuclear division. Other 
chapters deal with heredity and the inheritance of acquired 
characters and Mechanism and Life. 

There are a number of illustrations and a coloured plate; a 
full index is provided. 



102 NOTICES OF BOOKS. 

The Beginner's Guide to the Microscope, with a section on 
mounting slides. By Charles E. Heath, F.R.M.S. 1\ x 
5 in. 119 pages, 45 figures in text. London: Percival 
Marshall & Co., 1912. Price Is. net. 

In this elementary guide to the study of Microscopy the author- 
has treated the subject from a practical point of view, leaving 
theoretical matters to the larger books on the subject. With this 
little book at hand the beginner cannot fail to gain a useful 
knowledge of the instrument, its care and its application. The 
methods of illumination, including the dark-ground method, are 
fully dealt with. As the author says, the book is intended " to 
enable an ordinary man in an ordinary way to interest himself 
and his friends by giving sufficient instruction to make him capable 
of seeing and showing some of the hidden wonders " revealed by 
the microscope. 



103 




PROCEEDINGS \fy 

OF THE 

QUEKETT MICROSCOPICAL CLUB. 

At the meeting of the Club held on October 22nd, 1912, the 
President, Prof. A. Dendy, D.Sc., F.R.S., in the chair, the 
minutes of the meeting held on June 25th, 1912, were read and 
confirmed. 

Messrs. William Elliott and Leabury Edwardes were balloted 
for and duly elected members of the Club. 

Seventy-three members and live visitors were present. 
Thirteen proposals for membership were read by the Hon. 
Secretary. 

The list of donations to the Club was read and the thanks of 
the members were voted to the donors. 

A letter addressed to the President by Mr. Charles Peveril 
was read, intimating that the late Mr. J. M. Allen, F.R.M.S., 
had bequeathed to the Club his microscopes and apparatus 
belonging thereto. This legacy was accepted by the Committee ; 
it consists of two microscopes and some small accessories. 

The Librarian announced that he had received a copy of 
L. L. Clark's " Objects for the Microscope " to replace a copy 
missing from the library, also that Prof. Minchin's " Intro- 
duction to the Study of the Protozoa " had been presented by 
the author. 

A communication from Mr. J. Rheinberg, F.R.M.S., " On 
Resolutions Obtained with Dark-ground Illumination and their 
Relation to the Abbe Theory," in the absence of the author, was 
taken as read. 

A very interesting paper, " The Foraminifera in their Role 
as World-Builders," by Messrs. Earland and Heron- Allen, was 
read by Mr. Earland, and illustrated by a large number of 
.pictures of the various forms described, which were shown upon 



104 PROCEEDINGS OF THE 

a screen by Mr. Ogilvy by means of the Epidiascope, and by 
specimens of the deposits placed upon the table. 

The President said it was hardly necessary to ask them to- 
give a hearty vote of thanks to Mr. Earland for reading them 
such an interesting paper. A vote of thanks was carried by 
acclamation. 

Through the kindness of Messrs. Leitz's London representative, 
Mr. Ogilvy, the lecture was very efficiently illustrated by the 
use of the Leitz universal projection apparatus, which projected 
on the screen ordinary lantern -slides, plates and illustrations 
from books, etc., single photographs, microscopic sections at 
varying magnifications, rock hand-specimens and fossils. The 
capabilities of the apparatus, which employs an automatic L-arc,. 
taking 30 amp. at about 60 volts, were further demonstrated by 
Mr. Ogilvy and his assistants after the meeting. The approxi- 
mate candle-power produced is about 10,000. Micro-projection 
may be accomplished in the usual horizontal position, and, for 
hanging drop slides or other living preparations, a vertical 
position is also possible. Besides the projection of lantern-slides 
of any size up to 12 cm. square (4|in.), for which a novel and 
exceedingly efficient holder is provided, it is also possible to 
project larger transparencies up to 20 cm. square (8 in.), or such 
preparations as brain sections, etc. 

The President said they were all very much indebted to Mr. 
Ogilvy for what he had shown them ; he had himself been 
greatly interested to see how perfectly the Epidiascope was 
adapted for showing drawings, lantern-slides and microscopic 
specimens on the screen in a manner which he had not previously 
been aware of. 

The Hon. Secretary regretted to have to announce the recent 
death of Dr. M. C. Cooke, M.A., LL.D., A.L.S., one of t he- 
original founders of the Club, and President 1882-3. 



At the meeting of the Club held on November 26th, 1912, the 
President, Prof. A. Dendy, D.Sc, F.R.S., in the chair, the 
minutes of the meeting held on October 22nd were read and 
confirmed. 

Messrs. E. Pitt, G. C. Bellamy, T. Tonkin, H. Pulford,. 
E. H. Bassett, L. C. Hayward, William Hill, D. A. Mardon r 



QUEKETT MICROSCOPICAL CLUB. 105 

P. E. Dollin, F. Whitteron, J. M. Coon, E. W. H. Row and 
W. Hardinan were balloted for and duly elected members of 
the Club. 

The list of donations to the Club was read, and the thanks of 
the members were voted to the donors. 

The President said that members would be very glad to hear 
that the announcement made at their last meeting, of Dr. Cooke's 
death, was incorrect. They had it apparently on the best 
authority, and the scientific Press generally had been similarly 
misinformed. lie was sure that all members would hope that 
Dr. Cooke would long remain a member of the Club. 

The President asked members to extend a hearty welcome to 
a visitor, Dr. E. P. Hodges. Dr. Hodges was State Medical 
Supervisor for Indiana, U.S.A., had been for many years a 
Fellow of the Royal Microscopical Society, and took the greatest 
interest in microscopy generally. 

Mr. C. Lees dirties, for Messrs. Baker, exhibited a new 
one-sixteenth oil-immersion objective of N.A. 1*32. It was 
made of a stable glass one that would stand any climate. Its 
qualities were appreciated by members, who admired the 
excellent definition it gave (with a x 7 ocular) on a fine pre- 
paration of Trypanosoma gambiense. 

The President made some remarks relating to a new species of 
Holothurian. He said he had no formal paper to read, but the 
subject had been before the Club a few months ago {Journ. 
Q.M.C., Ser. 2, Vol. XI. p. 536), when an Australian visitor, 
Mr. F. Whitteron, of Geelong, had brought for distribution a 
number of specimens of a species of Holothurian which had an 
interesting history. They had been collected in Corio Bay, Port 
Phillip. Continental experts had identified the species as Trocho- 
dota dunedinensis (Parker). That identification, however, proved 
to be incorrect, and, as specimens had been distributed at their 
June meeting, he thought it proper to bring the matter before 
the notice of the Club. On examining the material he had then 
taken, he found that all the calcareous wheels had been dis- 
solved, possibly by the medium in which they were preserved 
being, or becoming, slightly acid. Fortunately, this failure was 
not of importance, as, in a reprint he had received from the 
Proceedings of the Royal Society of Victoria, Mr. E. C. Joshua, 
of Melbourne, discussed the species found at Geelong, and 



106 PROCEEDINGS OF THE 

definitely showed that it was not identical with the New Zealand 
form. He calls the Geelong species Taeniogyrus Allani. The 
President referred to the varying nomenclature of these species. 
He considered all the forms closely related, and preferred the 
generic name Chiridota, applied by Parker to the New Zealand 
form. The differences between the New Zealand and Geelong 
species were then considered. The structure of the wheel spicule 
had been worked out by Mr. Joshua, and was described in his 
paper. The President had worked out the N.Z. form some years 
ago, and described and sketched on the blackboard the various 
stages observed. The spicule has a broad margin, corresponding 
to the rim of the wheel. Then there are six spokes radiating 
from the centre, and in some species there is a small hole in the 
middle. Specimens of C. dunedinensis exhibit a uniform minute 
toothing all round the margin, which is inturned. The other 
side of the wheel has a different appearance. The six spokes 
show as before ; but the toothed edge is not seen at the top 
focus. Further, fresh detail is exhibited in the form of a 
six-rayed cross, which stands above the level of the spokes. A 
diagram of a vertical section was given. The President said it 
was a very curious and wonderful structure, and the development 
was of extreme interest. Commencing with the six-rayed cross, 
a thickening appears at the end of each ray, and on one surface 
only. This was the earliest stage observed. As the thickenings 
grow, they exert pressure on each other, and presently each 
spoke bifurcates at the extremity. The bifurcated ends begin 
to grow outward, and presently meet, and, fusing, form the rim 
of the wheel. The rim turns in, and is denticulated all round 
the margin. The spicule is, of course, useful as a skeletal 
structure ; but it is not at all apparent why such a remarkable 
and elaborate form should be required. The chief differences in 
C Allani, as compared with C. dunedinensis, are : The margin, 
instead of rounding off, remains hexagonal. The face showing 
the six-rayed cross is much the same, excepting that it also is 
hexagonal ; but the toothed rim is not uniform, but follows 
a curve with little bays opposite the angles of the hexagon, and 
the toothing is pronounced in parts, but is absent from the bays 
or notches. It is very difficult to account in any way for such 
minute differences as those noted. The new form, which he 
would prefer to call Chiridota Allani, was first found by Mr. 



QUEKETT MICROSCOPICAL CLUB. 107 

J. M. Allan, near Geelong, and subsequently by Mr. E. C. 
Joshua. 

Replying to a question, the President said that formalin was 
very unsafe to use in such cases, as it frequently becomes acid 
after a short time. 

Mr. J. Burton said he took some of the material brought by 
Mr. Whitteron, and, after some trouble, had found some 
wheels in the skin. They looked as though acid had been 
previously applied. The wheels showed a tendency to break 
down into anchors, reminding one of the well-known Synapta 
spicules. The anchor form, as the President had said, was an 
early stage in the development of the wheel. The wheels, under 
a, binocular, proved to be basin-shaped. There was a second 
kind of spicule, something like a drawer- handle in shape, and a 
third shape, found only in the tentacles, where it was very 
numerous, constituting, perhaps, 50 per cent, of their bulk. 

The thanks of the meeting were unanimously voted to the 
President for his communication. 

Several notes from Mr. E. M. Nelson were read to the meeting 
by the Hon. Secretary, as under : 

1. "On Microscopic Construction and the Side-Screw Fine 
Adjustment," in which he traced the history of this form from 
1841 to the present time, with some suggestions of his own for 
further improvement. 

2. On the Navicula used as a test by the Jurors of the 1862 
Exhibition, which he thought was the " English " rhomboides 
under the name of Xavicula affinis. 

3. " On a New Low-power Condenser : ' for use with objectives 
as low as 4 in., the ordinary condenser not filling the field with 
light when low powers were used. 

The way this difficulty may be surmounted is to construct 
the condenser upon the telephoto principle. This has now been 
done, and Messrs. Baker exhibited to the meeting a substage 
condenser, made from Mr. Nelson's design, which has 4 in. of 
focal length, and requires only 1 in. of working distance. With 
this condenser the image of the flat of the flame bears the same 
relation to a 4-in. objective with the large field of a P. and L. 
No. 1, A eyepiece, as the image with one of the ordinary uni- 
versal condensers with the top off does to a tw r o-thirds ; and 
this is precisely what was wanted. 



108 PROCEEDINGS OF THE 

The thanks of the Club were voted to Mr. Nelson for his 
communications. 



At the meeting of the Club held on January 28th the 
President, Prof. A. Dendy, D.Sc, F.R.S., in the chair, the 
minutes of the meeting held on November 26th, 1912, were 
read and confirmed. 

Messrs. Hilary Mavor, Robert Spry, E. J. Sheppard, F.R.M.S.,. 
A. C. Coles, M.D., D.Sc., A. M. Allison and H. W. Freeland 
were balloted for and duly elected members of the Club. 

The list of donations to the Club was read and the thanks 
of the members voted to the donors. 

Mr. Watson Baker, for Messrs. Watson & Sons, Ltd., ex- 
hibited and described a new model microscope which had a 
specially long horizontal travel, If in., to the mechanical stage, 
both movements working on the same axis. The fine adjustment 
is a vertical lever actuated by the now customary side-screw, 
and permitting the worker to always know whether the body 
is ascending or descending. It has a specially long range of coarse 
adjustment. The most important novelty on the stand was a 
new objective changer, made on the principle of a 3-jaw chuck ; 
less than a quarter-turn of a collar is all that is necessary to 
engage or release an objective, and it does not increase the tube 
length. An auxiliary stage was also shown. This, fitted to the 
usual stage, will give nearly four inches of horizontal travel, 
and should be found very useful in working with large pre- 
parations. 

Mr. A. A. C. Eliot Merlin, F.R.M.S., sent a photomicrograph 
taken at x 320 of Coscinodiscus heliozoides, showing extended 
" pseudopodia," from a preparation by Mr. J. D. Siddall. 

The fine radiating " pseudopodia " can be well seen when the 
print is examined in a good light with a Verant or other suitable 
hand magnifier. The photograph gives the impression that the 
radiating filaments are real appendages of the organism, and 
the general appearance of these reminds one strongly of the 
pseudopodia of Discorbina globidaris as figured in Carpenter 
(1901 edition), page 798. 

The photograph as a whole strikes one as more curious than 
beautiful. It will, however, be noticed with a lens that several 
of the radiating filaments are very fine and in exact focus. 



QUEKETT MICROSCOPICAL CLUB. 109 

The best focal plane for the " pseudopodia " does not coincide 
with that for the diatom itself, and this, together with the 
prolonged exposure necessary to bring out the faintly illuminated 
filaments, causes the valve to be much over-exposed, making 
the diatom appear as a mare blurred, globular white patch in 
the print. 

The President gave a resume of a communication of some 
length by Mr. W. M. Bale, F.H.M.S., of Victoria, Australia, 
entitled " Notes on Some of the Discoid Diatoms." This paper 
was a survey of some of the principal characters which have 
been utilised in the discrimination of species in three or four 
of the best-known genera of discoid diatoms. Some of the 
conclusions arrived at as to the inadequacy of many of these 
distinctions have been reached by previous observers, more 
especially in the genus Coscinodiscus ; but it was thought that 
in such cases the special instances now brought forward might 
be serviceable in reinforcing those conclusions. In other cases, 
particularly in the genus Actinoptychus, the author's observa- 
tions tended to prove that characters accepted as specific even 
by recent authors were demonstrably unreliable. The genera 
dealt with included Coscinodiscus, Actinocyclus, Asteromphalus 
and Actinoptychus. 

The thanks of the meeting were unanimously voted to the 
President for communicating this important paper. 

A paper on " British Freshwater Bhabdocoelida (Planarians), 
a Group of Turbellaria," by H. Whitehead, B.Sc, in the absence 
of the author was read by Mr. J. Wilson. 

After some discussion, in which Messrs. Scourfield and Ham- 
mond took part, the President said that the Bhabdocoelids were 
very low down in the scale, some of them ranking among the 
lowest of multicellular organisms. Most of his own work in 
Australasia had been done on land forms, but there were, pos- 
sibly, water forms as well. There were in Australia an enormous 
number of land Planarians which lived under stones, rocks, logs, 
etc., and only came out at night. Some were very large, reach- 
ing a length of one foot. They are locally incorrectly termed 
" land-leeches." Many are brightly coloured in stripes, spots, 
and patches of brilliant blue, red, yellow, orange, and sometimes 
iridescent. These colourations were very useful in assisting 
naturalists to identify species. He had described some forty new 



110 PROCEEDINGS OF THE 

species from Australia and New Zealand, and was very glad to 
see that the study of the group was being taken up in this- 
country. 

The Hon. Secretary read a " Note on Pleurosigma angalaturu" 
by Mr. E. M. Nelson, F.R.M.S., also a note on a coloured coma 
observed in examining A. Ralfsii, by the same author. 

Mr. C. F. Rousselet, F.R.M.S., read a paper on "The Rotifera 
of Devils Lake, and description of a new Brachionus." 



At the meeting of the Club held on February 25th, the Presi- 
dent, Prof. A. Dend} r , D.Sc, F.R.S., in the chair, the minuter 
of the meeting held on January 28th were read and confirmed. 
There were present ninety -three members and fourteen visitors. 

Messrs. H. T. Laurence, F. W. Mills, J. W. Durrad, W. Oatley, 
E. A. Anstey, C. D. Hutchin, A. Booker, F. W. Parrott, J. J. 
Armitage, N. Burns, J. Snell, A. 0. Trotman, R. A. Taylor, 
J. Bancroft, J. E. Barnard, R. Hall, V. Tyas and Dr. J. C. 
Kaufmann were balloted for and duly elected members of the 
Club. 

The list of donations to the Club was read and the thanks of 
the members voted to the donors. 

The President having appointed Messrs. Fuller and Watson - 
Baker, jun., as Scrutineers, the ballot for Officers and Council 
was proceeded with. 

The Hon. Secretary (Mr. \V. B. Stokes) read the Committee's 
forty-seventh Annual Report. It was considered that the past 
year was one of marked progress. Forty new members had been 
elected; five members had died and fifteen had resigned during 
the past year. The total membership on December 31st, 1912, 
was 406. 

The Hon. Treasurer (Mr. F. J. Perks) presented the Annual 
Statement of Accounts and the Balance-sheet for 1912, which 
had been duly audited and found correct. 

The Report and Balance-sheet were received and adopted, on 
the motion of Mr. Morland, seconded by Mr. Gaff. 

The President, having asked Prof. E. A. Minchin to take the 
chair, delivered his Annual Address, taking as his subject " By- 
products of Organic Evolution." 

Prof. Minchin said he was sure all present would agree that 



QUEKETT MICROSCOPICAL CLUB. Ill 

they had listened to a very fascinating address from one who 
was the foremost living authority in Europe on sponge spicules. 
The Club was very fortunate in having the subject dealt with by 
him. The objects were quite well known to all microscopists, and 
he believed he was right in saying that all the different forms of 
spicules described could be obtained from sponges found on our 
own coasts. He had great pleasure in moving a hearty vote of 
thanks to their President for his address, and in asking him to 
allow it to be published in the Journal. 

The motion having been put to the meeting, was carried by 
acclamation. 

The President, in acceding to this request, thanked the mem- 
bers for the way they had received the address, but said he had 
thought himself that Prof. Minchin was the greatest authority 
they had on these microscopic objects. 

A vote of thanks to the Auditors and Scrutineers, having been 
moved by Mr. W. R. Traviss and seconded by Mr. A. M. Jones, 
was put to the meeting and carried unanimously. 

Mr. Bremner then moved that their best thanks be given 
to the officers of the Club for their services during the year. 
They had given them a very valuable amount of time with a 
most excellent result. Mr. Stokes had referred to the work 
done by their Librarian, which must have occupied hundreds 
of hours, and as for Mr. Stokes himself his unfailing courtesy 
and his capacity for hard work were deserving of their highest 
appreciation. 

Mr. A. D. Michael said he always felt very strongly that 
the great success which attended the scientific societies of London 
was mainly due to the work done by their officers. He had 
much pleasure in seconding the vote of thanks to those who had 
so ably conducted the business of the Club during the year. 

Mr. W. B. Stokes said that as this was the last occasion on 
which he would be able to speak as an officer of the Club he 
would reply for his colleagues ; he thanked the members for 
the vote they had just carried. He felt he was leaving the 
Secretaryship in better hands than his own ; but was very glad 
that he was leaving it not when the Club was at the bottom 
of a curve of prosperity, but very nearly at the top. He thanked 
the officers for the ready assistance which they had always given 
him, and which had rendered his duty a pleasant one, and he 



112 PROCEEDINGS OF THE QUEKETT MICROSCOPICAL CLUB. 



desired also to thank the members for the kind way in which 
they had supported him during his term of office as their 
Secretary. 

The President announced the result of the ballot for Officers 
and Committee to be as follows : 



President 



Vice-Presidents 



Treasurer . 
Secretary 

Assistant Secretary 
Foreign Secretary 
Reporter .... 
Librarian . 
Curator .... 
Editor .... 



Vice four senior 
Members retired. 

Vice James Burton 
{apptd. Secretary.) 



Prof. Arthur Dendy, D.Sc, F.R.S., 
F.L.S. 

C. F. Rousselet, F.R.M.S. 

E. J. Spitta, L.R.C.P., M.R.C.S.,F.R.A.S. 

D. J. Scourfield, F.Z.S., F.R.M.S. 
.Prof. E. A. Minchin, M.A., F.R.S. 

Frederick J. Perks. 
James Burton. 
J. H. Pledge, F.R.M.S/ 
C. F. Rousselet, F.R.M.S. 
R. T. Lewis, F.R.M.S. 
S. C. Akehurst. 
C. J. Sidwell, F.R.M.S. 
A. W. Sheppard, F.Z.S., F.R.M.S. 
R. Paulson, F.R.M.S. 
J. Grundy. 

M. Blood, F.C.S., F.R.M.S. 
.0. D. Soar, F.L.S., F.R.M.S. 
R. Inwards, F.R.A.S. 



11 



o 



FORTY-SEVENTH ANNUAL REPORT, 

Reviewing the work of the Club during the year 1912 shows 
that it has been a period in which its high value to the user 
of the microscope has been again demonstrated. Not only has 
the Club maintained the interest of its meetings, but it has 
exhibited a revival of interest in matters connected with the 
instrument itself. There has been a very good attendance at 
conversational meetings, and the favour shown to the excursions 
during a season having a record rainfall is well worthy of note. 
The number of new members added during the twelve months 
is forty, 50 per cent, advance on that of 1911, and this number 
would have been even greater if an ordinary meeting in Decem- 
ber had been possible. The Club has lost five members by 
death, and resignations have accounted for fifteen ; this leaves 
a net gain of twenty members. The total membership on 
December 31st was 406. 

The following communications have been made during the 
year : 

Jan. James Burton. Notes on Algae collected in 1911. 

Feb. Prof. E. A. Minchin, F..R.S. Some Speculations with 

regard to the Simplest Forms of Living Beings and 
the Origin of Life. 
March. H. Sidebottom. Lagenae of the South-west Pacific. 
C. F. Rousselet, F.R.M.S. On New Species of Rotifera. 

,, D. Bryce. On New Species of Callidina. 

A. E. Conrady, F.R.A.S. On Resolving Powers ob- 

tainable with Dark-Ground Illumination. 
A. A. C. Eliot Merlin, F.R.M.S. On the Capped 

Secondaries of Navicula Smithii. 
April. John Stevens, F.R.M.S. On Notommata glgantea 
(Glascott). 
Duncan J. Reid. Illumination in Critical Work. 

May. E. M. Nelson, F.R.M.S. On the sculled fseudopodia 
of certain Diatoms. 
Journ. Q. M. C, Series II. No. 72. 8 



114 FORTY-SEVENTH ANNUAL REPORT. 

May. R. T. Lewis, F.R.M.S. Notes on Solpuga. 

,, A. E. Oonrady, F.R.A.S. Some Experiments on Alter- 

native Microscopical Theories. 
June. W. B. Stokes. Resolutions obtained with Dark- 
Ground Illumination and their Relation to the 
Spectrum Theory. 
R. W. H. Row. On a Saw-fly. 

Oct. Julius Rheinberg, F.R.M.S. On Resolutions obtained 

with Dark-Ground Illumination and their Relation 
to the Abbe Theory. 
A. Earland, F.R.M.S., and E. Heron-Allen, F.L.S. 
Foraminifera as World Builders. 
Nov. Prof. Arthur Dendy, F.R.S. On a New Species of 

Holothurian. 
E. M. Nelson, F.R.M.S. On Microscope Construction. 

On Namcula rhomboides. 



55 

M 55 5? >5 

On a New Low-Power Con- 



55 55 5) 55 

denser. 



The following exhibits were made : 



Jan. E. M. Nelson, F.R.M.S. Photomicrographs. 

,, A. Earland, F.R.M.S. Photomicrographs of Recent 

Foraminifera. 
W. Watson & Sons, Ltd. Microscope Tray. 

,, Charles Baker. Nelson's Dark-Ground Illuminator. 

March. T. W. Butcher, F.R.M.S. Photomicrographs of Nam- 
cula Smithii. 
Charles Baker. Nelson's Oil Immersion Dark-Ground 

Illuminator. 
,, Charles Baker. Nelson's Improved Chromatic Con- 

denser. 
Charles Baker. Nelson's Improved Rousselet Com- 

pressor. 
April. C. D. Soar, F.R.M.S. Drawings of Water-Mites. 
A. W. Stokes. Electric Lamps for the Microscope. 

C. F. Rousselet, F.R.M.S. Diatoms with "Pseudo- 

podia." 
Charles Baker. A New l|-in. Objective of N.A, 0'18. 

Oct. E. Leitz. The Epidiascope. 



FORTY-SEVENTH ANNUAL REPORT. 115 

Nov. Charles Baker. A New l/16th-inch Oil Immersion 
Objective. 
,, Charles Baker. Nelson's New Low-Power Condenser. 

Your Committee wish to thank the authors and exhibitors 
for these interesting communications and exhibits. It will be 
seen that there has been no falling-off in either the quality or 
quantity of papers submitted to the Club. 

There were eleven excursions during the season, and all were 
well attended, except on one occasion when the weather was 
very bad ; the record number of fifty-three members met to visit 
the Royal Botanic Gardens. The total attendances for all ex- 
cursions was 235, which is also a record for any one year, and the 
average of 21*4 per excursion has only been exceeded once before. 

The collecting, though not including anything new, was always 
satisfactory. 

The thanks of the Club are due to the Secretary of the Royal 
Botanic Gardens and to the Metropolitan Water Board for 
permission to visit their enclosures ; also to the Port of London 
Authority and Mr. Carlyle, who so kindly entertained the 
members at tea after their visit to the Surrey Commercial Docks. 
Later in the year a party of members gave an exhibition of 
Pond Life at the Dock Club and Institute, on which occasion 
Messrs. Soar, Offord and Wilson gave short lectures with lantern 
illustrations. 

The Hon. Librarian and his assistant have expended a con- 
siderable amount of time and labour upon the classification and 
arrangement of the Club's books, and great progress has been 
made with the preparation of the new catalogue. The amount 
allotted to the cost of binding has been exceeded by 5, and 
repairs and cases for loose parts have cost about <11. The 
question of the elimination of periodicals containing nothing of 
particular interest to microscopists is before your Committee ; 
the limitation of space for housing the Club's books being a 
difficulty that it has to meet. The Library has been used in 
1912 as much as in previous years, but the cost of housing 
relatively to the use that is made of the books presents quite 
a serious problem for consideration by your Committee. 

During the year under review the following volumes have been 
added : 



116 FORTY-SEVENTH ANNUAL REPORT. 

LIST OF BOOKS PURCHASED SINCE APRIL 1912. 

SlJSSWASSERFAUNA DEUTSCHLANDS : 

Part II. Copepoda, Ostracoda, Malacostraca. 
,, XIV. Rotatoria and Gastrotricha. 

Science of the Sea. Edited by G. H. Fowler. Issued by the 
Challenger Society. 

Huyghen's Treatise on Light. Translated by Prof. Silvanus P. 
Thompson. 

Also fifty copies of Henry Sidebottcm's paper, " Lagenae of 

the South-West Pacific Ocean," reprinted from the Q. M. C. 

Journal, April 1912, Vol. XI. These copies may be purchased 
at 2s. Qd. each. 

LIST OF BOOKS PRESENTED SINCE APRIL 1912. 

Presented by the Author, E. Penard : 
Notes sur quelques Sarcodines. Part I. 

Presented by ft. T. Lewis : 
Objects for the Microscope. 2nd Ed. . . L. Lane Clark. 

Presented by Julius Rheinberg : 
Spectrum Method of Colour Photography. 

Presented by the Author, Prof. E. A. Minchin : 
Introduction to Study of Protozoa. 

Presented by James Motham : 
List of the Fossil Radiolaria from Barbados. A. Earland. 

Figured in Ehrenberg's Fortsetzung. 
Radiolaria ....... A. Earland. 

Reprinted from the Q. M. C. Journal, April 1900. 

Presented by Mrs. D. Wesche : 

Phylogeny of the Nemocera . . . W. Wesche. 

With notes on the leg bristles, hairs and certain mouth glands 
of Diptera. 



FORTY-SEVENTH ANNUAL REPORT. 117 

Presented by the Author, E. Penard : 
Notes sur quelques Sarcodines. Part II., 1906. 

Presented by the Author, Dr. J. B. De-Toni : 

Sylloge Algarum : 

Vol. T. Sections I. and II. Chlorophyceae. 

,, II. Bacillarieae. 

,, III. Fucoideae. 

,, IV. Sections I., II., III., IV., Florideae. 

,, V. Myxoph}-ceae. 

Presented by the Author, C. E. Heath : 
Beginners' Guide to the Microscope. 

During the year ending December 1912 the Library has 
received the following publications : 

Quarterly Journal of Microscopical Science. 

Victorian Naturalist. 

Mikrokosmos. 

Royal Microscopical Society. 

British Association. 

Royal Institution. 

Geologists' 1 A ssociation. 

Manchester Literary and Philosophical Society. 

Hertfordshire Natural History Society. 

Bristol Naturalists' Society. 

Birmingham Natural History and Philosophical Society. 

Botanical Society of Edinburgh. 

Glasgow Naturalists Society. 

Croydon Natural History Society. 

Indian Museum (Calcutta). 

Royal Society of New South Wales. 

American Microscopical Society. 

Sin ithsonian Instit ution. 

Academy of Natural Science, Philadelphia. 

Missouri Botanic Garden. 

Philippine Journal of Science. 

Bergen Museum. 

Lloyd Library, Cincinnati. 



118 FORTY-SEVENTH ANNUAL REPORT. 

U.S. National Herbarium. 

Royal Society. Series B. 

Natural History Society of Glasgoiv. 

Zoologisch-botanischen Gesellschaft, Wien. 

Redia. 

U.S. National Museum. 

Nuova Notarisia. 

Nyt Magazin. 

Birmingham and Midland Institute and Scientific Society. 

Liverpool Microscopical Society. 

Nova Scotian Institute of Sciences. 

Royal Dublin Society. 

Canadian Institute. 

University of California. 

Tijdschrift. 

Illinois State Laboratory of Natural History. 

Scottish Microscopical Society. 

The Club's collection of slides has been increased by 133 
preparations, including a further donation of fifty Freshwater 
Rhizopods from Dr. Penard. An interesting donation consisted 
of several fine injected anatomical preparations mounted by the 
late Sir Benjamin W. Richardson over fifty years ago, which are 
still in perfect condition. It is proposed to publish in future 
issues of the Journal lists of additions to the Cabinet, and these 
lists will serve as a supplementary catalogue of slides ; the first 
list was published in the November issue. Two microscopes with 
several objectives and accessories were bequeathed to the Club 
by the late J. Mason Allen, so that the Club is now well 
provided with microscopes for exhibiting objects at the meetings. 

The thanks of the Club are due as in former years to the 
editors of the English Mechanic and Knowledge for publishing 
excellent reports of the ordinary meetings. Those in the former 
journal are of great use in keeping country members au courant 
with the doings of the Club. 

Your Committee desires to thank the officers for their services 
during the past year, and desires to call attention to the 
following resolution which was passed by them at their meeting 
on January 28th : 

" That the Committee accept with grtat regret the resignation 



FORTY-SEVENTH ANNUAL REPORT. 119 

of Mr. W. B. Stokes as Secretary of the Club, and in so doing 
desire to express their hearty thanks to Mr. Stokes for his 
valuable services." 

Your Committee sees nothing to prevent the Club maintaining 
its traditional usefulness. There is no question as to the need 
of such an institution ; but there is need to remind members 
of the importance of the Club being all it seems to be to the 
new-comer, and not a cause of disappointment. The latter 
condition need never obtain if the dual role of the Club be 
maintained, presenting an effective means of publicity for the 
specialist and a help to the less experienced amateur. 



120 



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121 



ON SOME FORAMINIFERA FROM THE NORTH SEA 
DREDGED BY THE FISHERIES CRUISER "HUX- 
LEY" (INTERNATIONAL NORTH SEA INVESTIGA- 
TIONSENGLAND). 

By Edward Heron-Allen, F.L.S., F.G.S., F.R.M.S., and 
Arthur Earland, F.R.M.S. 

{Head March 25th, 1913.) 

Plates 10, 11. 

In connexion with our paper on the distribution of Psammo- 
sphaera and Saccammina in the Northern Area of the North 
Sea,* Mr. J. 0. Borley, M.A., of the Fisheries Department, 
Board of Agriculture (England), suggested a continuation of our 
investigations into the Southern Area. With some reluctance we 
undertook the work, having little expectation of any tangible 
results, as Mr. Borley had already, from his personal experience 
of dredging in these waters, confirmed the generally held belief 
that rhizopodal life was of very sparing occurrence in the area 
in question. The shallowness of the sea and the consequently 
excessive wave action in this area were thought to be factors 
limiting the development of rhizopodal life, as compared with 
the conditions in the Scottish North Sea, where the average depth 
is greater and the disturbance due to the action of waves and 
currents is consequently less. 

By the courtesy of the officers of the Board the dredgings 
made by the Fisheries Cruiser " Huxley " were placed at our dis- 
posal, and, guided by the admirable charts plotted by Mr. Borley 
to show the distribution of " silt areas " in the North Sea, six 

J 

* "On some Foraminifera from the North Sea, etc., dredged by the 

Fisheries Cruiser " Goldseeker " (International North Sea Investigations 
Scotland). II. On the distribution of Saccammina sphaerica (M. Sars) and 
Psa)iimos])haera fusca (Schulze) in the North Sea." Journ. R. Micr. Soc. 
1913, pp. K26, pis. i.-iv. 

Journ. Q. M. C, Series II. No. 73. 9 



122 E. HERON- ALLEN AND A. EARLAND ON SOME FORAMINIFERA 

dredgings were selected, three from the most northerly area 
dredged by the " Huxley" and three from an area considerably 
farther south. 

The three Northerly Stations selected lie far to the N.E. of 
the Dogger Bank, in the centre of the North Sea, and in what 
is, strictly speaking, the Scottish area of that sea. They lie in 
the neighbourhood of the Great Fisher Bank, and are contiguous 
to the most southerly line of " Goldseeker" Stations (Stns. 41, 
41 B , 41 A , 42, etc.) but farther out to sea towards the east. These 
three stations are referred to in the following paper as the 
Northern or Outer Area. 

The three Southern Stations selected lie in the deep trough of 
water between the Dogger Bank and the Northumbrian coast, 
and are quite close to the shore. They are referred to in the 
paper as the Southern or Inner Area. 

These dredgings were carefully selected with the view of obtain- 
ing the muddiest deposits possible, such conditions being most 
favourable for rhizopodal life ; and they probably represent the 
richest of the " Huxley " dredgings, all the others which were 
cursorily examined consisting of clean siliceous sand with hardly 
any trace of microzoa. Such deposits, Mr. Borley assures us, are 
typical of the greater part of the Southern North Sea. 

Owing to the widely separated stations selected the microfauna 
of these six dredgings may probably also be regarded as typical 
of the inshore and midsea areas. The comparative richness of 
the fauna of the Southern Area, as compared with the Northern, 
is undoubtedly due to the proximity of the coastline and the 
abundant food supply derived from the coastal deposits. 

All the dredgings consisted of loose sands containing a con- 
siderable amount of mud ; but whereas the sands from the 
Northern Area were easily cleaned (like the majority of the 
"Goldseeker" dredgings from adjacent stations), the sands of 
the Southern Area proved somewhat refractory. They con- 
tained numerous pellets of hardened mud which resisted dis- 
integration, and even the action of a strong solution of boiling 



FROM THE NORTH SEA. 123 

soda did not completely remove the adherent mud from the sand- 
grains and foraminifera. 

This is a noticeable feature, because as a rule muddy dredgings 
are readily broken down if thoroughly dried before the cleaning 
process is commenced, and even the most stubborn muds generally 
succumb to the action of boiling soda. 

We have, however, met with similarly refractory muds at a few 
of the " Goldseeker" stations in the Moray Firth, and are unable 
to satisfy ourselves as to the cause of this viscosity, which is 
quite possibly due to different causes in separate localities. 
Among the various explanations which have occurred to us are : 

1. The presence of the Hag (Myxine glutinosa). This loath- 
some fish is very common at some of the " Goldseeker " stations 
where the viscosity has been observed, and as when captured 
or touched it exudes an incredible quantity of slime, it is quite 
possible that the presence of this fish in any numbers might 
locally influence the nature of the sea-bottom. But Mr. Borley 
tells us that Myxine is rare in the vicinity of the Stations 
sampled, so it may be dismissed from consideration so far as the 
" Huxley " material is concerned. 

2. Chemical changes in the mud owing to its having passed 
through the digestive organs of worms and Echinoderms, many 
of which obtain their nutriment by swallowing mud and extract- 
ing the organic matter. Thus, in the deep water of some of the 
Norwegian fjords, the bottom deposit consists of a very fine 
mud full of the tests of rhizopods and swarming with Annelids. 
When the mud is dried and broken down again in water, and 
the foraminifera have been removed by floating and elutriation, 
a mass of fine granular material is left which under the micro- 
scope proves to consist of small oval pellets of mud, the excreta 
of worms (PL 11, fig. 2).* These pellets resist the action of 
soda, making it evident that the mud must have become altered, 

* Such deposits are presumably similar to those referred to by Dr. Johan 
Hjort under the name of "coprolitic muds." See The Depths of the Ocean, 
by Dr. J. Hjort and Sir John Murray (1912), p. 148. 



124 E. HERON- ALLEN AND A. EARLAND ON SOME FORAMINIFERA 

/ 

or at any rate that the separate particles must have become 
agglutinated during their passage through the alimentary canals 
of the worms. Annelid remains are of fairly frequent occurrence 
in the "Huxley" dredgings from the Southern Area, but not 
noticeably so. 

3. It is a matter of common knowledge that fresh mud or 
clay, if dried, breaks down readily in water ; but that, if it is 
worked or "puddled" before being dried, it becomes plastic, and 
then resists disintegration. It is possible that wave or current 
action might thus serve to cover the surface of sand-grains and 
foraminifera with a coating of mud in a plastic or colloidal 
condition, and on the whole we are inclined to favour this 
explanation, so far as the viscosity of the " Huxley" deposits is 
concerned. 

The whole question, however, though interesting from the 
point of view of the chemist and physicist, lies rather outside 
the province of the zoologist, although it seems evident that the 
phenomenon might be of great importance from the geological 
point of view, as such viscosity would favour the preservation of 
the encrusted microzoa. 

A very noticeable feature in the " Huxley " dredgings is the 
roundness of the sand-grains as compared with those of "Goldseeker" 
dredgings from similar deposits. This is conclusive evidence that 
the grains have travelled a great distance, or have been sub- 
jected to tidal action within restricted geographical limits for a 
prolonged period in comparatively shallow water. The phe- 
nomenon has been observed in connexion with the Goodwin 
Sands. The scour of the tides and currents round the Dogger 
and Great Fisher Banks is doubtless the cause of the rotundity 
of the " Huxley " sands, the individual grains of which are often 
as smooth and polished as the Aeolian sands of the desert 
(PI. 11, fig. 3).* 

* Laboratory experiments have proved that a quartz grain -$ in. in 
diameter requires an amount of abrasion equal to that acquired in 
travelling- a distance of 3,000 miles in water before it becomes rounded to 
the form of a miniature pebble. (Daubree, Geologw Experimentale, Paris, 



FROM THE NORTH SEA. 125 

To return to the microscopical investigation of the " Huxley " 
material : as already stated, this was originally undertaken solely 
with the view of extending our study of the distribution of two 
species, viz. Psammosphaera fusca (Schulze) and Saccammhut 
sphaerica (M. Sars), and the results, so far as they affect those 
species, have already been published in our paper dealing with 
these forms.* But in the course of an examination of the 
material we found so many other forms that we determined to 
make a systematic list of the species recorded. This list, which 
we now publish, contains no less than 133 species or varieties, 
many of which have not been recorded previously from the areas 
in question. 

It must not be concluded, from the occurrence of so extended 
a list, that the material was rich in foraminifera. So far from 
this being the case, the majority of the dredgings, previous to 
manipulation, gave little or no striking indication of organic 
remains beyond the presence of a few shell- fragments, spines of 
Echinoderms, annelid tubes, and an occasional rhizopod. The 
dredgings quite justified in superficial appearance the opinion 
which Mr. Borley and other zoologists familiar with the North 
Sea had formed, viz. that it was practically devoid of foraminifera. 
But careful and repeated elutriations of the dredgings resulted 
in the separation of small quantities of light material at each 
station, and, as is often the case, these minute samples yielded 
a more diverse fauna than .is often found in richer gatherings. 
Except in the case of a few dominant species, however, the 
number of actual specimens observed was very small. Even in 
the case of the dominant species the proportion of individuals 
observed to the total bulk of the dredging was too insignificant 
to be estimated. The relative abundance of the species in the 

1807, p. 47, and Phillips, Q. J. Geol. Soc, vol. xxxvii., p. 21). But the 
dynamics of the troubled waters of the North Sea are probably quite 
different from the controlled action of a revolving cylinder in a laboratory 
experiment ! 

* Journ. R. Micr. Soc, 1913, p. 25. 



126 E. HERON-ALLEN AND A. EARLAND ON SOME FORAMINIFERA 

annexed lists, as indicated by the letters C, R, VR, etc., must 
be understood to refer to their abundance as inter-contrasted with 
other foraminifera, and not to their frequency in the whole bulk 
of the dredging. 

A noticeable feature in the dredgings of the Southern or Inner 
Area is the relative frequency of specimens of fossil foraminifera. 
They are principally small types derived from cretaceous strata 
and such as are commonly found in shore sands and shallow- 
water dredgings round the southern coasts of England. But a 
few larger and well-developed fossil specimens of Nodosaria and 
Cristellaria were noted in Hauls 869 and 871, which are not 
cretaceous. These are perhaps derived from the Crag, a sub- 
marine outcrop of which formation is believed to extend across 
the North Sea * ; but they are not all deeply stained with iron, 
as is usually the case with the larger foraminifera of the Crag, 
and may be derived from the Gault. 

Only one fossil was recorded from the Northern Area, viz. 
Spirolocidina impressa Terquem. This is no doubt derived from 
some submerged Tertiary deposit. It may be noted that Tertiary 
foraminifera have been dredged by the " Goldseeker " in the Moray 
Firth. 

The fossils recorded are : 

Spiroloculina impressa Tei quern, Northern Area, one specimen. 
Textularia globulosa Ehrenberg, Southern Area, all stations. 
Nodosaria pauperata d'Orbigny, Southern Area, two stations. 
Nodosaria plebeia Reuss, Southern Area, one station. 
Cristellaria costata Fichtel and Moll sp., Southern Area, one 

specimen. 
Cristellaria rotulata Lamarck sp., Southern Area, one station. 
Globigerina aequilateralis Brady, Southern Area, one station. 
Globigerina cretacea d'Orbigny, Southern Area, two stations. 

* The appearance of many shell fragments dredged from a band of the 
sea bed stretching roughly from the Suffolk ccast to the Continent 
suggests that they come from the Crag. These, however, are iron-stained 
and curiously glazed in appearance in seme, but not in all cases, owing 
to attritiop. 



FROM THE NORTH SEA. 



~>7 



127 



One of these species, viz. Cristellaria rotulata Lamarck sp., was 
also recorded as a recent form. 

An examination of the list of species at the different stations 
reveals several noticeable features. Taking the three stations in 
the Northern Area first, it will be seen that they vary greatly 
in richness, Haul 767 yielding only 14 species, as against 26 in 
Haul 770 and 54 in Haul 772. Even the richest haul in the 
Northern Area contrasts badly with the poorest haul in the 
Southern Area, which yielded 72 species, the other Southern 
hauls yielding 79 and 94 species respectively. 

This discrepancy is largely explained by the abundant records 
of the Family Lagenidae in the Southern Area. The figures are 
very striking, fossils being disregarded : 





Northern Area. 


Southern Area 


Lagena . 


8 


30 


Nodosaria 





3 


Lingulina 





1 


Margin ulina 





1 


Vaginulina 





1 


Cristellaria 





2 


Polymorphina . 


2 


4 


Uvigerina 


2 


2 



Total 



12 



44 



The abundance of Lagenidae in this Area off the Northumber- 
land coast has already been noted by Brady.* But in the 
" Huxley " dredgings only the genus Lagena is noticeably 
abundant, the other genera of the family not being well 
represented. 

The other families exhibit a similar discrepancy in the lists of 
species recorded from the two Areas, but it is not so noticeable 
as in the case of the Lagenidae. 



* Report British Association, 1862, p. 122; also Trans. Tyneside 
Naturalists Field Club, 1863, vol v., part 4, p. 292; Ibid., 1864. vol. vi., 
part 2, p. 194. 



128 E. HERON-ALLEN AND A. EARLAND ON SOME FORAMINIFERA 

The dominant forms in the two Areas are as follows * : 



Northern. 

8. Miliolina seminulum Linne 
sp. 

21. Reophax sco?yiurus Mont- 
fort. 

26. 



37. 

42. 
69. 
82. 
97. 

100. 

106. 
118. 

123. 

124. 
126. 

132. 



Verneuilina polystropha 

Reuss sp. 
Bulimina fusiformis W ill . 



Polymorphina compressa 

d'Orbigny. 
Polymorphina sororia 

Reuss. 

Truncatulina lobatula W. 

& J. sp. 
Rotalia Beccarii Linne sp. 

Nonionina depressula W. 

& J. sp. 
Polystomella striatopunc- 

tata F. & M. sp. 



Southern. 

Miliolina seminulum Linne sp. 
Reophax scorpiurus Montfort. 

Haplophragmiiim p>se udosp irale 

Will. sp. 
Verneuilina polystropha Reuss 

sp. 
Bidimina fusiformis Will. 
Lagena laevigata Reuss sp. 
Lagena striata d'Orbigny sp. 



Globigerina rubra d'Orbigny. 
Truncatulina lobatula W. & J. 

sp. 
V C at one station only. 
Rotalia orbicularis d'Orbigny. 
Nonionina depressula W. & J. 

sp. 
Polystomella striatopunctata F. 

& M. sp. 



Several of these forms are more abundant in one Area than in 
the other, as may be seen by reference to the table. 

Some of the discrepancies in the above comparative list can be 
explained by what we know of the distribution of the species in 
other rhizopodal faunas. Thus (26) Haplophragmiiim pseudo- 
spirale Will. sp. (PI. 10, fig. 2-4) appears to be confined to coastal 
deposits. It is very common in many muddy shallow-water 
dredgings round the W. coast of Ireland and Scotland and in 
the Shetlands, but the u Goldseeker " records in the North Sea are 



* The numbers refer to the tabular list at the end of the paper. 



FROM THE NORTH SEA. 129 

very few and entirely confined to coastal gatherings. It does not 
occur in any of the midsea " Goldseeker " dredgings from stations 
adjacent to the Northern Area of the " Huxley" 

Of the other species recorded in the list a few have more than 
a passing interest. (1) Nubecularia lucifuya Defrance is a southern 
form, not previously recorded on the S. and E. coast of Britain 
beyond Bognor, Sussex. A few specimens have been dredged by 
the "Goldseeker " in the Moray Firth and Shetland seas, and these 
two records, from intermediate localities, are therefore of interest. 

The same remarks apply to (9) Massilina secans d'Orbigny sp. 
This is the most abundant and typical Miliolid of the shore 
sands and shallow water all round the S. and W. coast-line. 
There are few records of shore sands on the E. coast, but the 
species occurs at Cromer and St. Andrews (Fife) and is abundant 
at Scapa in Orkney in shore sand. It is extremely rare in the 
" Goldseeker '" North Sea dredgings, but the few specimens found 
were from a Station (39 B ) near the " Huxley " Northern Area. 
Its absence from the Southern Area is noticeable, and probably 
due to the muddiness of the deposit. 

(12) Comuspira striolata Brady. The specimen from Haul 767 
(Northern Area) is of the very fragile and etiolated type abun- 
dant in many of the " Goldseeker " dredgings from the deeper 
North Sea. 

(13) Comuspira diffusa Heron- Allen and Earland * (P\. 11, 
fig. 1). The specimens of this form, which has been recently 
described by us, were large and quite typical, but few in number. 
The Northern Area is quite close to the " Goldseeker " Stations at 
which it is most abundant, but the species is sparingly distributed 
round the British coast. 

(14) Bathysiphon argenteus, (62) Layena cymbula (PL 10, 
figs. 10-12), (84) Layena unyuis, and (117) Discorbina Praeyeri 

* " On some Foraminifera from the North Sea, etc., dredged by the 
Fisheries Cruiser. " Goldseeker " (International North Sea Investigations 
Scotland). III. On Comuspira diffusa, a new type from the North Sea." 
Journ. R. Mior. Soc., 1913, pp. 272-6, pi. xii. 



130 E. HERON-ALLEN AND A. EARLAND ON SOME FORAMINIFERA 

are new forms discovered first by us in " Goldseeker " dredgings. 
They are described and figured in our report on the Foraminifera 
of the Clare Island Survey (Proc. Roy. Irish Acad., 1913, vol. xxxi., 
No. 64). 

(20) Reophax nodulosa Brady (PI. 10, fig. 1) is extremely 
rare as a British species. It has been recorded from the Clyde 
Area and Skye by Robertson and from the Estuary of the Dee 
by Siddall. The British specimens are very minute, but in the 
deep sea it attains a great size, up to 1 in. in length. 

(23) Haplophragmium anceps Brady, another deep-water form, 
is of rare occurrence in British waters. It has been recorded 
from shore sands at Southport (Chaster) and Bognor (Earland), 
and we have recently dredged it in the Clare Island Area. 

(25) Haplophragmium crassimargo Norman (PL 10, fig. 5-6), 
a large and very robust form closely allied to H. canariense 
d'Orbigny sp., is the typical Haplophragmium of the deeper parts 
of the North Sea, and is abundant in many of the " Goldseeker " 
dredgings. 

(27) Thurammina papillata Brady. The single specimen re- 
corded from Haul 369 in the Southern Area is extremely small, 
but quite typical of the spherical type (cf. Brady, Foraminifera 
of the u Challenger" 1884, pi. xxxvi., fig. 7). The papillae are 
prominent and very numerous. The genus Thurammina is 
abundant and very variable in the deep water of the North Sea 
to the N.E. of Shetland, but very rare in the central North Sea. 

(28) Ammodiscus incertus d'Orbigny. All the specimens are 
very minute and of a light-grey colour. The genus is very 
sparingly distributed in all the " Goldseeker " dredgings from the 
North Sea, and all the specimens are minute. In the Faroe 
Channel, however, it attains its full dimensions. 

(35) Spiroplecta biformis Parker and Jones sp. (PI. 10, 
fig. 9). The single specimen of this rare form, recorded from 
Haul 772 in the Northern Area, is noticeable for the rapid 
increase in size of the Textularian chambers following the Spiro- 
plectine portion of the test. 



FROM THE NORTH SEA. 131 

(37) Vemeuilina polystropha Reuss sp. All the specimens of 
this species, one of the most abundant and typical North Sea 
forms, belong to the large coarsely built type, except in Haul 770 
Northern Area, where also a few individuals of the minute and 
delicate type described and figured by us in the Clare Island 
Survey Report were observed. 

(38) Clavulina obscura Chaster (PI. 10, figs. 7, 8), occurs in 
both Areas, but whereas the Northern Area yielded only a single 
specimen, the species attains an extraordinary development both 
as regards size and abundance in Haul 871 in the Southern 
Area. It is usually a very rare species, though widely distributed 
round our coasts in muddy gatherings. 

(91) Lingulina carinata d'Orbigny. The single specimen from 
Haul 869 Southern Area is of a minute type. Such specimens 
occur sparingly in most of the " Goldseeker" dredgings from 
muddy areas. 

(92) Marginulina glabra d'Orbigny. The single specimen from 
Haul 871 is very minute. Rut the species is abundant and 
attains a very large size in the deeper waters of the North Sea 
to the N.E. of Shetland. 

(106) Globigerina rubra d'Orbigny (PI. 10, figs. 13-15). This 
species is one of the commonest Globigerinae all over the North 
Sea and often forms a large proportion of the finer material 
dredged on muddy bottoms. 

(110) Discorbina Chasterl Heron-Allen and Earland. Origin- 
ally described by the late Dr. Chaster of Southport under the 
specific name Discorbina minutissima. This specific name having 
been previously used by Seguenza for another form, we have 
(in the Report on the Foraminifera of the Clare Island Survey) 
renamed the species after its original discoverer. It is of common 
occurrence in muddy dredgings from all the shallow coastal 
deposits of the North Sea and around the Western shores of 
Britain generally. 

(112) Discorbina Mediterranensis d'Orbigny sp. and (115) Dis- 
corbina Peruviana d'Orbigny sp. are old specips which we propose 



132 E. HERON-ALLEN AND A. EARLAND ON SOME FORAMINIFERA 

to revive for sub-types of the " rosacea " group, under a scheme 
which is fully explained in our Clare Island Report. 

(133) Polystomella crispa Linne sp. The occurrence of only a 
single specimen of this species in the Southern Area is very 
noticeable, as it might have been expected to occur more plenti- 
fully so near the coast. But as regards the single specimen from 
the Northern Area, its occurrence there is still more noteworthy, 
as the species is extremely rare in the " Goldseeker " dredgings 
even in the proximity of the coast and none have been previously 
found so far out at sea as this. The specimen is, however, 
very water- worn, and may have been current-borne for a great, 
distance. 



List of " Huxley " Stations from which Material 

was Examined. 



( 



A. Northern or Outer Area lying N.N.E. of the Dogger 
Bank. 

1. Haul 767, Station xix., 56 53' N., 3 43' E. Dredging made 

July 22nd, 1906, in 35 fathoms, to the S.W. of the Great 
Fisher Bank. 

2. Haul 770, Station xxii., 56 50' N., 3 59' E. Dredging made 

July 24th, 1906, in 31 fathoms, on the Inner Shoal to the 
S. of the Great Fisher Bank. 

3. Haul 772, Station xxv, 56 34' N.', 3 53' E. Dredging made 

July 24th, 1906, in 37 fathoms, to the S. of the Inner 
\ Shoal and Great Fisher Bank. 

/ B. Southern or Inner Area lying W. of the Dogger Bank, 
between the Bank and the English coast. 

4. Haul 869, Station xlii., 55 6' N., 1 2' W. Dredging made 

July 23rd, 1907, in 43 fathoms, off Blyth, Northumberland. 

5. Haul 871, Station xliv., 54 59' N., 1 7' W. Dredging made 

July 23rd, 1907, in 34 fathoms, off Tynemouth. 

6. Haul 882, Station (?), 55 21' N., 1 10 'W. Dredging made 
\ July 26th, 1907, in 45 fathoms, off Alnmouth. 



FROM THE NORTH SEA. 



133 



The asterisk denotes the presence of fossil specimens. 1 = a single 
specimen only. V C = very common. C = common. F == frequent. R = 
rare. VE = very rare. 



MlLIOLIDAE. 

Sub-family Nubecv larinae. 

1. Xubecularia lucifuya Def ranee 

Sub-family Miliolin inae. 

2. Biloculina depressa d'Orbigny 

3. Biloculina rinyens Lamarck sp. 

4. Spiroloculina impressa Terquem 

5. Miliolina bicomis Walker & Jacob sp 

6. Miliolina circularis Bornemann sp. 

7. Miliolina contort a d'Orbigny sp. 

8. Miliolina seminulum Linne sp. 

9. Massilina secans d'Orbigny sp. 

Sub-family Pen eroplid inae. 

10. Cornuspira involvens Reuss 

11. Cornuspira Seise ye nsis Heron- Allen & 

Earland ...... 

12. Cornuspira striolata Brady 

13. Cornuspira diffusa Heron-Allen & Ear- 

land 

ASTRORHIZIDAE. 
Sub-family Pilvlin inae. 

14. Bathy siphon aryenteus Heron-Allen & 

Earland 

Sub-family Saccammininae. 

15. Psammosphaeva fusca Schulze 

16. Saccammina sphaerica M. Sars 

Sub-family Bhabdamm in i nae. 

17. Hyperammina ramosa Brad} r . 

LlTUOLIDAE. 
Sub-family Litvolinae. 

18. Beophax dipluyiformis Brady 

19. Beopha.v fusiformis Williamson sp. 

20. Beophax nodulosa Brady 

21. Beophax scorpiurus Montfort 

22. Beophax Scottii Chaster 

23. Haplophraymium anceps Brady 

24. Haplophraymium Canariense d'Orbignv 

sp 

25. Haplophrayminm crassimargo Xorman 

26. Haplophraymium pseudospirale William 

son sp. ..... 









vc 



c 



vc 



VR 



VC 



F 

R 






1* 

c 
vc 

2 



F 



VC 



R 



1 
VC 

vc 

F 



1 
1 



5^ : 

03 so 



1 

2 



VR 



R 
F 



VC 
VR 



VR 



VC 



5_- 



F 
R 



R 

2 

VC 



VC 



1 
VC 

C 



VR 

VC 
F 

1 

e 



vc vc 



3d 



VR 
VC 

1 
1 



VR 



134 E. HERON-ALLEN AND A. EARLAND ON SOME FORAMINIFERA 





i 

Sn 


go 


P <N 


p 


3^' 


3 




c3 ro 


c3 t- 


rit~ 


ci co 


r- 


=5 oo 




r- 


B" 


s i - 


K= 


w 


K 00 




1 

'. 


2 


3 


4 


5 


6 


Sub- family Trochammin inae. 








27. Thurammina papillata Brady 








1 






28. Ammodiscus incertus d'Orbigny sp. 




R 


F 








29. Trochammina ochracea. Williamson sp. . 




F 


C 


R 


vc 




30. Trochammina squamata Jones k, Parker 










F 


VC 


Textularidae. 














Sub-family Textv lari nae. 














31. Textularia agglutinans d'Orbigny . 










VR 




32. Textularia conica d'Orbigny . 








VR 


VR 


vc 


33. Textularia globulosa Ehrenberg 








Y* 


F* 


1* 


34. Textularia gramen d'Orbigny . 










VR 




35. Spiroplecta biformis Parker & Jones sp. . 






1 








36. Gaudryina filiform in Berthelin 






- 




F 


R 


37. Yerneuilina polystropha Reuss sp. 


vc 


R 


VC 


VC 


VC 


VC 


38. Clavulina obscura Chaster 






1 


F 


VC 




Sub-family Bu limin inae. 














39. Bulimina aculeata d'Orbigny 








VR 


R 


c 


40. Bulimina elegans d'Orbigny . 











F 


C 


R 


41. Bulimina elegantissima d'Orbigny 








c 


R 


F 




42. Bulimina fusiformis Williamson 




vc 


C 


vc 


VC 


VC 


VC 


43. Bulimina marginata d'Orbigny 




c 


F 


c 


F 


F 


C 


44. Bulimina, ovata d'Orbigny 










F 






45. Bulimina pupoides d'Orbigny 








R 


R 


1 




46. Virgvlina Schreibersiana Czjzek 








R 






R 


47. Bolivina difformis Williamson sp. 










VR 


VR 


1 


48. Bolivina dilatata Reuss . 










R 


C 


C 


49. Bolivina nobilis Hantken 












1 


1 


50. Bolicina plicata d'Orbigny 








1 


VR 


F 


F 


51. Bolivina punctata d'Orbigny . 








C 


R 


F 


F 


52. Bolivina textilarioides Reuss . 








R 








53. Bolivina variabilis Williamson sp. 










R 


F 




Sub-family Cassibulin inae. 














54. Cassidulina crassa d'Orbigny . 






F 


F 


F 


F 


55. Cassidulina laevigata d'Orbigny 




VR 


R 




1 




56. Cassidulina subglobosa Brady. 






R 


R 


F 




Lagenidae. 














Sub-family Lag en inae. 














57. Lagena acuticosta Reuss 




VR 










58. Lagena apiculata Reuss sp. . 










VR 


2 


59. Lagena bicarinata Terquem sp. 








1 






60. Lage?ia clavata d'Orbigny sp. 








R 


C 


F 


61. Lagena costata Williamson sp. 










F 


R 


62. Lagena cymbula Heron-Allen & Earland 








1 






63. Lagena distoma Parker & Jones 






1 


R 


C 


VC 


64. Lagena fasciata Egger . 






R 


VR 




1 


65. Lagena globosa Walker & Jacob sp. 






1 


VR 


F 


1 


66. J^agena gracUlima Seguenza sp. 






j 




1 


C 





FROM THE NORTH SEA. 



135 



"'-' 5 3<* 2 
~*- S l - K 1 - K 



67. Lagena 

68. Lagena 

69. Lagena 
Lagena 

79. Lagena 

71. Lagena 
Lagena 

72. Lagena 

73. Lagena 

74. Lagena 

75. Lagena 

76. Lagena 

77. Lagena 

78. Lagena 

79. Lagena 

80. Lagena 
81 Lagena 

82. Lagena 

83. Lagena 

84. Lagena 

85. Lagena 



gracilis Williamson . 
hexagona Williamson sp. 
laevigata Reuss sp. . 
laevigata, trigonal form 
laevis Montagu sp. 
lagenoides Williamson sp. 
lagenoides, trigonal form. 
lineata Williamson sp. 
lucid a Williamson sp. 
Malcomsonii J. Wright 
marginata Walker & Boys sp. 
marginato-perforata Seguenza 
Orbignyana Seguenza sp. 
ornata Williamson sp. 
quadrata Williamson sp. 
se mist riat a Williamson 
squamosa Montagu sp. 
striata d'Orbigny sp. . 
sulcata Walker & Jacob sp. 
unguis Heron-Allen *Sc Earland 
Williamsuni Alcock sp. 



Sub-family Xodosarinae. 

86. Xodosaria Jiliformis d'Orbigny 

87. Xodosaria pan perata d'Orbigny 

88. Xodosaria pltbeia Reuss. 

89. Xodosaria p grula d'Orbigny . 

90. Xodosaria scalaris Batsch sp. 

91. Lingulina carinata d'Orbigny 

92. Marginulina glabra d'Orbigny 

93. Vaginuliiia legumen Linne sp. 

94. Cristellaria acut auricular is Fichtel & 

Moll sp 

95. Cristellaria costata Ficbtel & Moll sp. 

96. Cristellaria rotulata Lamarck sp. . 

Sub-family Poltmorp hi n inae. 

97. Polgmorphina compressa d'Orbigny 

98. Polgmorphina lactea Walker & Jacob sp 

99. Polgmorphina oblonga Williamson . 

100. Polgmorphina sororia Reuss . 

101. T'vigerina angulosa Williamson 

102. Ucigerina pygmcea d'Orbigny 

Olobigerixidae. 

103. Globigerina aequilateralis Brady . 

104. Globigerina bulla ides d'Orbigny 

105. Globigerina cretacea d"Orbigny 

106. Globigerina rubra d'Orbigny . 

107. Pullenia xphaeroides d'Orbigny sp. 



VC 

1 



R 



ve 



c 



R 



YC 



F 



F 
F 



VC 



VC 

1 

1 



R 

1 



VR 
VE 

C 
VR 

R 



VR 
VR 



VR 

1 

VR 

F 

VC 
VR 

F 



1* 

R 

1 

VR 

1 

1* 
R* 

R 

1 
R 



C 

Y* 

VC 



X X 



1 

F 
VC 

c 

VR 

F 

F 

F 

1 
F 

1 

C 
F 
C 
C 
1 

c 



1 
1* 

\ T R* 

1 

2 



1* 
R 

1* 
C 



1 

VC 

F 

1 

1 



1 
F 

F 

VC 



C 
R 

C 

1 

c 



R 



VC 1 
R 



R 



C 

C 

1 



136 B. HERON-ALLEN AND A. EARLAND ON SOME FORAMTNIFERA 



ROTALIDAE. 
Sub-family Spj rillin inae. 

108. Spirillina vivipara Ehrenberg 

Sub-family Rotalinae. 

109. Patellina corrugata Williamson 

110. Discorbina Chasteri Heron-Allen & Ear- 

land ...... 

111. Discorbina globularis d'Orbigny 

112. Discorbina Mediterranensis d' Orbigny sp 

113. Discorbina nitida Williamson sp. . 

114. Discorbina obtusa d'Orbigny sp. 

115. Discorbina Peruviana d'Orbigny sp. 

116. Discorbina poly rraphes Reuss 

117. Discorbina Praegeri Heron- Allen & Ear 

land ...... 

118. Truncatulina lobatida Walker & Jacob 

sp. ..... 

119. Truncatulina refulgens Montfort sp. 

120. Truncatulina Ungcriana d'Orbigny sp, 

121. Pulvimdina haliotidea Heron-Allen & 

Earland ..... 

122. Pulvinulina Karsteni Reuss sp. 

123. Rotalia Beccarii Linne sp. 

124. Rotalia orbicularis d'Orbigny 

NUMMULINIDAE. 
Sub-family Poltstomellinae. 

125. Nonionina asterizans Fichtel & Moll sp. 

126. Nonionina depressula Walker & Jacob 

SP 

127. Nonionina pauper ata Balkwill & Wright 

128. Nonionina scapha Fichtel & Moll sp. 

129. Nonionina stelligera d'Orbigny 

130. Nonionina turgida Williamson sp. . 

131. Nonionina umbilicatula Montagu sp. 

132. Polystomella striatopunctata Fichtel & 

Moll, sp 

133. Polystomella crispa Linne sp. 



3*-' 



VC 



3 



c 



vc 



vc 



F 



F 



R 
C 



VC 



vc 
1 



3 



F 



F 

1 



VC 



R 



C 
C 



R 
VC 



VC 



2*' 



VR 



VR 
C 



F 



R 
VC 



VR 
C 
1 

VR 

1 

R 
1 






VR 



C 

R 
C 
R 
C 
F 
C 



C 
VR 



F 
VR 
VC 



F 

F 
R 
R 
1 



VC 



CO 

cc 



c 

1 

1 

c 
1 



R 
C 
F 



1 
R 

C 



1 
F 



1 
F 



C 



FROM THE NORTH SEA. 137 

DESCEIPTION OF PLATES. 

Plate 10. 

Fig. 1. Reophax nodulosa Brady, x 120. 
2, 3, 4. Haplop>hragmium pseudospi?*ale Will, sp., x 40. 
,, 5, 6. Haplophragmium crassimargo Norman, x 30. 
,, 7, 8. Clavulina obscura Chaster, x 100. 
9. Spiroplecta b iformis Parker & Jones sp., x 120. 
10. Lagena cymbida Heron- Allen & Earland, superior view, 

X 250. 
11. Lagena cymbida Heron- Allen & Earland, inferior view, 

x 250. 
,,12. Lagena cymbida Heron-Allen & Earland, edge view, 

x 250. 
13, 14, 15. Globigerina rubra d'Orbigny, x 120. 

Plate 11. 

Fig. 1. Cornuspira diffusa Heron-Allen & Earland, x 5, illus- 
trating the protean habit of growth. 

2. Heavy portion of ooze from Hilte Fjord, Norway, 260 
metres, " Goldseeker" Haul 141, depth 260 metres. 
Most of the foraminifera have been removed by 
elutriation, leaving a residuum of faecal pellets of 
Annelid origin (1 Hyalinoecia sp.) x 45. 

,, 3. Rounded sand-grains from "Huxley" material, x 12. 

,, 4. Normal angular grains typical of shore gatherings and 
shallow-water deposits, x 12. 

,, 5. Crystalline sand-grains from a dredging in the Hauraki 
Gulf, New Zealand, x 1 2. Such crystalline grains are 
very rare except in the neighbourhood of volcanic 
deposits. 

[It is greatly to be hoped that the writers will find it possible 
for them to examine in similar detail a certain number of the 
remaining "Huxley" dredgings, of which some six hundred are 
available, taken from the North Sea south of the Forth. Their 
present paper shows that in their practised hands results of con- 
siderable interest may be expected should this be done. I would 

Journ. Q. M. C, Series II. No. 73. 10 



138 E. HERON-ALLEN AND A. EARLAND ON SOME FORAM1NIFERA. 

submit for their consideration the examination of selected stations 
along lines drawn east and west, in the manner of sections. A 
large proportion of these in all probability could be dealt with 
in a very summary manner, but the remainder might yield 
results of importance as to the relation of distribution to salinity, 
depth, temperature and current, possibly even affording evidence 
of the main trend of the currents, which would provide a welcome 
check on other observations carried out by current-meters and 
drift -bottles. 

In regard to the samples which they have examined from 
the deep water east of the Dogger it may be remarked that the 
Admiralty tide charts show but low rates of velocity in the 
district, which has moreover a greater depth of water than one 
would expect to be consistent with frequent wave action at the 
bottom. Recent current measurements carried out by the 
Board of Agriculture and Fisheries have also failed to detect 
any marked resultant current. It may therefore be suggested 
that the sub-polish attained by the rounded grains is not in 
all cases due to attrition on the spot. The freedom of the 
adjacent Dogger Bank from silt, a grade of material found in 
high percentage on either side, may perhaps be explained by 
the finer particles churned up and held in suspension by wave 
action during storms being gradually washed into the deeper 
water : some segregation of the rounder grains may take place 
in the same manner. A thorough geological examination of 
the area, especially of the Scottish coast, might also show to 
what extent, if any, the grains result from the disintegration 
of certain definite sandstone rocks. 

For the action of wave and current in the Southern Bight 
(North Sea south of 53) the collection of samples as a whole 
furnish good evidence ; the material is to a great extent graded 
as in a levigator, the average diameter of the sand particles 
diminishing as the speed of the current declines. Yet even in 
this district, with its shallower waters and far more powerful 
currents, the upper limit of size of the particles affected is soon 
reached, and one feels in consequence the need of searching for 
other causes before explaining the rotundity of certain of the 
grains near the Dogger by tidal action alone. J. O. Borley.] 

r . , . _____ _ , _, 

jQurn. Quefcett Mkyo-icopical CliLib, Ser. 2, YoLX.IL, Np. 73, November ]>Z3, 



Journ. Q.M.C. 



Ser. 2, Vol. XII., PI. 10. 




FORAMINIFERA FROM THE NORTH SEA, 



Tourn. Q.M.C. 



Ser. 2, Vol. XII., PI. 11. 











BpX^Smt 






N 




A^fc. ^*> ^? 1 


P> 


',. 


*^ . - 


IF 










i^E^L^^ 


.4 


t? 




P^B . a^P^H P^PAw^a. .^^Pmb ^1 P^H t *^? 1 
^^^B PMV PS -k^_ fi^W 

Bp^^^ r m ^ J 


BS^; Kpjfe/w ^^^^ Pfet. ^ 


W*iM PJ*V^ PA. 3L > Bl 


4 fe^ ^ 





CORNUSPIRA DIFFUSA HERON-ALLEX AND EaRLAND. 

Sand-grains, etc., from the Bottom-deposits, 



139 



DESCRIPTION OF ARRHENURUS SOOURFIELDI AND 
ACERCUS LONG/TARSUS : TWO NEW SPECIES OF 
WATER-MITES. 

By C. D. Soar, F.L.S., F.R.M.S. 

(Read April 22nd, 1913). 

Plates 12, 13. 

Arrhenurus Scourfieldi sp. nov. 

In the autumn of 1912, Mr. D. J. Scourfield handed me a tube 
containing a few water-mites, which he had taken from fresh 
water in Cornwall. Amongst them was one which was quite new 
to me, a male Arrhenurus, of the sub-genus Megalurus. As I 
cannot find that it has been described or figured, I propose to name 
it after Mr. Scourfield. 

Arrhenurus Scourfieldi sp. nov. The specimen is a male ; 
length 1-04 mm., greatest breadth about 064 mm. In outline 
the body is long ; anterior corners well cut off, and slightly bent 
inwards ; sides almost straight, tapering towards the posterior 
margin. The posterior margin is divided by a central cleft into 
two well-rounded portions. 

The skin is covered with small papillae ; the dorsal surface has 
the usual indented sunk line common to members of this genus, 
and several dermal glands both inside and outside the sunken line. 
Looked at from above there is a small wing-like process about 
0'15 mm. from the posterior margin. 

The colour is a dark blue-green with brown markings on the 
dorsal surface. The epimera are slightly lighter in colour. It 
is of the same colour as Arrhenurus globator. 

The eyes are very dark red, close to margin, about 0*32 mm. 
apart. Capitulum, about 0"20 mm. long. 

The first pair of epimera are joined together at the back of the 
capitulum, the second pair pressed close to first pair so that what 



140 C. D. SOAR, DESCRIPTION OF ARRHENURUS SCOURFIELDI AND 



is known as the first two pairs of the epimera form one distinct 
group. 

The posterior pair are in two distinct groups placed about 
0*05 mm. behind the second pair. 

The genital area lies about 0*08 mm. behind the fourth pair of 
epimera, the plates stretching the whole distance across the 
body of the mite. The length of each plate is about 0*25 mm., 
tongue shaped and covered with numerous acetabula. 

The legs are of the usual structure of the genus with the spur 
on the fourth segment of the fourth leg. They are strong and 
well provided with swimming hairs. The first leg about 0"60 mm. 
long, fourth leg 0'84 mm. 

Locality : Near the Lizard, Cornwall, 1912. Female unknown. 

Acercus longitarsus sp. nov. 

Acercus longitarsus sp. nov. The body is 0*76 mm. in length ; 
breadth about 0'54 mm., ovate. The colour is a pale straw 
yellow with dark-brown markings. There is a reddish-yellow 
wedge-shaped patch in the centre of the dorsal surface. 

The epimera cover nearly the whole of the ventral surface, and 
differ from that of the type species Acercus omatits in the follow- 
ing important particulars. Firstly, the genital area instead of 
being situated in a small bay on the posterior margin of the 
epimera as in Acercus ornatus, is partly enclosed in an angular 
space formed by the posterior edge of the epimera being turned at 
a low angle towards the median line. Secondly, near the base 
of the epimera are two small incurvations, one on each side, which 
are not found in the type species of this genus. They run into 
the epimera about O05 mm. The actual genital area itself is 
similar to type species, having six acetabula arranged in the same 
way. 

The palpi are about 0*45 mm. in length. On the flexar edge 
of the fourth segment are placed two long hairs, a little distance 
apart ; they are close together in Acercus ornatus. 

The legs of the species form the most striking departure from 
the type form and in fact all other species of this genus ; on 
comparison it will be seen that the tarsi are enormously developed 
in length. 

The last segment of the first and second pairs of legs are longer 



ACERCUS LONGITARSUS \ TWO NEW SPECIES OF WATER-MITES. 141 

than usual, but it is the last segment of the fourth pair which 
shows the great increase in length. The tarsi measure as much 
as 0*60 mm., which is more than the fourth and fifth segment 
together. 

The first leg is about 1*40 mm. in length, the second about 1*30, 
the third about 0"90, the fourth about 1-58. 

The eyes, large and distinct, are very dark red and about 0'14 
mm. apart. 

This mite can be most easily recognised by the length of the 
tarsus of the fourth pair of legs. I propose naming it Acercus 
longitarsus. 

Locality : South Devonshire (female unknown). 

There are also one or two additions to be made to British 
records. Mr. Williamson, F.R.S.E., in working out the material 
on the Genus Sperchon, has found that we have two species quite 
new to the British area, and two that up to the present have only 
been recorded for Ireland. 

1st. Sperchon clupeifer Pier. 
Sub-genus : Hispidosperchon. 
Locality : Oban and Norfolk Broads. 

2nd. Sperchon tenuabilis Koen. 

Sub-genus : Hispidosperchon. 

Locality : Oban. Recorded for Ireland by Halbert in Clare 
Island survey. 

3rd. Sperchon papillosus Sig Thor. 
Sub-genus : Squamosus. 
Locality : Oban. Recorded for Ireland by Halbert. 

4th. Sperchon Thienemanni Koen. 
Sub -genus : Rugosa. 
Locality : Derbyshire. 



142 c. d. soar, description of two new species of water-mites. 

Description of Plates. 

Plate 12. 

Fig. 1. Arrhenurus Scourfieldi sp. nov. Dorsal surface of male 
drawn from a living specimen, x 50. 
2. Arrhenurus Scourfieldi sip. nov. Ventral surface of same 
drawn after mounting. 

Plate 13. 

Fig. 1. Acercus longitarsus sp. nov. Dorsal surface of males, 
X 58. 
2. Acercus longitarsus sp. nov. Ventral surface of same, 

x 58. 
3. Acercus longitarsus sp. nov. Palpi of same, X 150. 



Jovrn. Quelett Microscopical Club, Ser. ?, Vol. XII., Ho. 73, November 1913 



Journ. Q.M.C. 



Ser. 2, Vol. XII., PI. 12. 





^A7 2 

C. D. S., del. adnat. 

$ Arrhenurus Scourfieldi sp. nov. 



Journ. Q.M.C. 



Ser. 2, Vol. XII., PI. 13. 




C. D. S., del. ad nat. 

S ACERCUS LONGITARSUS sp. nOV. 



143 



THE COLLECTION AND PRESERVATION OF THE 

HYDROIDA. 

By G. T. Harris. 

Communicated by C. J. IT. Sidwell. 
{Bead April 22nd, 1913.) 

The Hydroida are too well known, as both beautiful and interesting 
objects, to need any eulogy on my part. If they have received 
less attention from the members of the Q.M.C. than some other 
groups, it is probably due to the fact that the Hydroida evince 
a decided and conservative preference for salt water, and show 
no inclination whatever for the uneventful environment of 
metropolitan ponds. Hence, those who would collect them must 
seek them where they may be found, i.e. from tidal limits to as 
many fathoms as the collector's means or stomach will allow. 

Bearing in mind that this paper is written more for the help 
of the novice than as a communication offering original matter, 
I would safeguard myself from any charge of carelessness by 
warning the uninitiated that collecting, say, rotifers, and col- 
lecting hydroids are two totally dissimilar things. Pond 
collecting is a more or less safe and a very pleasant recreation ; 
hydroid collecting is rarely enjoyable, and may be, by a little 
carelessness, rendered adventurous. The one could be prosecuted 
in a silk hat and a frock coat if desired, without seriously giving 
the wearer away ; the costume best suited to the other tries the 
loyalty of one's staunchest friend. Dredging is, perhaps, less 
open to contumely than shore collecting ; the nature of the 
operation secures to the collector a considerable measure of 
privacy, while the examination of the spoil can be carried out 
in attitudes familiar to oneself and those around. Shore collect- 
ing permits of no compromise, and the positions most consonant 
with successful collecting are mainly such as contribute materially 
to the entertainment of the seaside visitor waiting to be 
amused. 

I think it may be taken for granted that, in spite of its 



144 G. T. HARRIS ON THE COLLECTION AND 

obvious drawbacks, shore collecting will appeal to the amateur 
collector rather than the more professional method of dredging. 
It entails less expense, requires less intimacy with the local 
conditions, and, for a given amount of time expended, probably 
yields a richer harvest ; finally, the physiological effects of shore- 
collecting are not so overwhelming as are those sometimes 
connected with dredging. At the same time, no serious student 
of the Hydroida can ignore the dredge as a means of collecting, 
as a large number of species can only be obtained by its aid. 
However, for the reassurance of those who confine themselves to 
shore collecting, I may state, as the result of long experience, 
that on a favourable shore the number of species to be found 
between tide-marks is very great, and amongst them are many of 
the most beautiful forms amongst the Hydroida. - 

Unfortunately no precise directions can be given for successful 
shore collecting. It is entirely a matter of experience, and even 
the practised collector may fail dismally until he has learnt the 
shore upon which he is engaged. Why hydroids should be found 
plentifully in a certain section of shore, yet be absent from the 
same shore a quarter of a mile away, with apparently the same 
conditions, I am unable to say, yet such appears to be the case. In 
my own district, where rock-pools are plentiful, I have a case 
in point. Coryne vaginata, one of the commonest littoral 
hydroids along the south coast, occurs in two or three of the 
larger pools of a certain locality, yet although the rock-pools to 
the right and left for some distance are, as far as I can see, 
identical, no Coryne occurs in them. Nor is this accidental, or 
peculiar to one season, as I have been able to go to these 
particular pools for the last six years with the certainty of 
obtaining Coryne vaginata. Some years ago when collecting at 
Criccieth, in North Wales, I spent day after day laboriously 
trying to collect hydroids where none grew ; finally, I transferred 
my operations to a less likely looking section of the shore, and 
collected hydroids during the remainder of my visit over a very 
limited area. An instance singularly illustrative of this elusive 
quality of shore collecting recently came under my notice, which 
may serve to impress upon inexperienced collectors the desirability 
of not jumping too hastily to the conclusion that they are on a 
barren shore. A party of professional naturalists spent the 
whole of one summer in investigating the fauna of a certain 



PRESERVATION OF THE HYDRQIDA. 145 

section of coast, the results of which were embodied in a report. 
The shore collecting was apparently confined to one spot, from 
which but one hydroid, and that the ubiquitous Sertularia pamila, 
was recorded ; yet a quarter of a mile farther east is an excep- 
tionally prolific hunting-ground at low tide, where at least a 
dozen species of hydroids may be taken. All this points to the 
fact that wherever the hydroid-hunter elects to collect he must, 
as a preliminary, first ascertain that he has found the hydroid 
ground. When he has satisfied himself that he has done so, then 
collecting may begin in earnest. 

It is too readily assumed that only those shores are good for 
hydroid-hunting upon which rock-pools occur. My experience 
leads me to protest against this assumption, for I have often 
had much better collecting on shores strewn with large fucus- 
covered boulders than in some rock-pool districts. Rock-pools do 
not necessarily imply the existence in them of hydroids, not even 
when they are clean, sanitary abodes. The rock-pools at Sid- 
mouth are excavated in Permian sandstone at the base of cliffs 
500 ft. high, composed principally of Keuper marl, and in the 
early summer are lined, as is everything in them, with fine 
mud, the result of the red marl falling from the cliffs during 
winter and being washed into the pools. This should make 
hydroid life impossible, but it does not ; they seem to thrive in 
it (I sometimes think upon it), and cleaning them for the 
microscope thoroughly disheartens one. Last autumn I was 
collecting in South Devon, where the cliffs are composed of 
hard conglomerate, giving fine clean rock-pools. One rock-pool 
near low-water mark especially attracted my attention. Filled 
with clear, limpid water, its sides draped with seaweeds, every 
condition seemed perfect for hydroid life, and yet not a single 
specimen was found in it. I satisfied myself of this by abso- 
lutely cleaning the pool out, examining every piece of seaweed, 
as I removed it, in a small tank of water, then going carefully 
over the sides and bottom of the pool with a lens of large 
diameter. It is little discrepancies like these that both try and 
puzzle the shore collector. 

Hincks has given advice upon shore collecting that cannot 
well be improved upon, and is as precise as such advice can 
be. He recommends lying at full length when collecting, and 
however objectionable this may seem to be in theory, it is 



146 G. T. HARRIS ON THE COLLECTION AND 

thoroughly sound in practice, and I always adopt it, carrying 
a mackintosh sheet for the purpose. It should be recollected 
that a superficial examination of any rock-pool is not sufficient 
to detect minute species, and even species of considerable size, 
such as Plumularia setacea, often harmonise so well with their 
surroundings as to be difficult of detection. As far as possible 
it is best to assume a comfortable position, and then thoroughly 
examine the basin and the seaweeds it contains, using a lens of 
about 4 inches diameter when necessary. Many rock-pools have 
projecting ledges draped with fucus ; such are found to be espe- 
cially prolific if well examined. The fucus should be turned 
right back, so as to expose the sides it covered and the under 
surface of the ledge, which are normally in deep shade. Sponges 
growing underneath may be scraped off and examined for com- 
mensal hydroids. If long, dark tunnels exist in the rock, the 
arm should be pushed up and the upper surface of the rock felt 
over with the hand for any adherent masses of sponge, etc., 
which may be broken off and examined. This is a distinctly 
sporting method, as it gives the crab, when there, a chance to 
get in first with his pincers. Bring him out and hold him under 
water in the rock-pool while you go over him carefully with a 
lens ; his carapace will probably recompense you for the pinched 
finger. Shells, also, should be carefully examined. The only 
time I ever took Podocoryne areolata was upon a shell found lying 
at the bottom of a funnel-shaped rock-pool, and Professor 
Allman had the same experience. Many species are so minute 
as to defy detection by the ordinary methods of shore collecting 
and are best obtained by taking small tufts of seaweeds and 
looking over them at home with the compound microscope. 

I have remarked previously that collecting is often very re- 
munerative on shores strewn with large fucus-covered boulders. 
Those who know Llandudno and Criccieth will recognise excellent 
examples of such shores, and doubtless many similar exist round 
the coast. The boulders near low-water mark yield the richer 
harvest, and the underneath is the surface to work. Where 
two of these huge boulders have fallen close together, so as to 
form a miniature tunnel, the latter is sure to afford a prolific 
hunting-ground. My method is to lie on my back and gradually 
work into the tunnel, carrying a blunt knife and some fair-sized 
bottles, or jars, of sea-water, The surface of the rock is chipped, 



PRESERVATION OF THE HYDROIDA. 147 

or scraped, where promising growth appears, and the gathering 
dropped into the bottles, to be examined elsewhere and in a 
more comfortable position. This is really an excellent method 
of obtaining material. 

Dredging is not likely to be undertaken by the occasional 
collector unless he is a very enthusiastic one, and if undertaken 
the individual will probably be in no need of advice from me, as 
he will know more or less about it. To the beginner I would 
say, choose a dredge of moderate size and confine dredging 
operations to moderate depths, i.e. up to ten fathoms. If any 
fishing industry is carried on where the collector happens to be, 
he may get ample employment from a bucket of trawl refuse 
obtained from one of the boats ; even the rejectamenta of 
lobster-pots is a good hunting-ground. On an open sandy coast, 
after a gale or heavy sea, deep-water specimens may be obtained 
in excellent condition if the jetsam left by a receding tide is 
carefully looked over. They should be promptly placed in bottles 
of sea-water, to recover and expand their tentacles, and this 
process may be aided by vigorously aerating the water by means 
of a syringe. 

Having collected the material, the less eventful work of pre- 
paring it for the microscope follows as a matter of course, and 
I believe I am doing beginners a service in urging upon them 
the desirability of arranging for this to take place at the earliest 
possible moment after collecting. Once the hydroids begin to 
feel the effects of overcrowding and badly aerated water the 
polyps withdraw into their calycles, and require a large expendi- 
ture of time and patience to coax them to expand again. The 
best results are undoubtedly got when the collector is in a 
position to go straight from the shore to his microscope and deal 
with the material collected. The polyps are then vigorous from 
their normal environment, less intolerant of the narcotising 
agent, and a considerable quantity of material can be dealt with 
in a comparatively short time, as there is no tedious waiting 
for the polyps to expand. My own method is to divide the 
collection into two lots, separating the Gymnoblastea from the 
Calyptoblastea, as the former can be best prepared by killing 
without the intervention of a narcotic. The hydroids are placed 
in watch-glasses (or better still small Petri dishes) with clean 
fresh sea- water, and cleansed as far as can be without injuring 



148 G. T. HARRIS ON THE COLLECTION AND 

the polyps by gently brushing the polypary with a camel's hair 
brush. They are allowed to recover from the shock, and then 
a few drops of 1-per-cent. cocain hydrochlorate added to each 
watch-glass and the glasses set gently aside until all the species 
have been dealt with. When the polyps are fresh and vigorous 
narcotisation is not a difficult process, nor one requiring extreme 
care, but should the hydroids be left twenty-four hours or so 
before dealing with them the process is likely to be not only 
tedious but generally unsuccessful. When the polypites are 
judged to be sufficiently narcotised to permit of killing the 
tentacles should be pricked with a needle somewhat roughly, to 
be quite certain that narcotisation is sufficient to prevent retrac- 
tion of the tentacles. I learnt by experience that even when 
insensibility was apparently well established, on the application 
of the killing and fixing agent the polypites would withdraw at 
least partially, perhaps wholly, into the calycles, so that it is 
necessary to be quite sure that narcotisation is complete before 
using the fixing fluid. The killing and fixing agent most con- 
venient is undoubtedly osmic acid, either a plain 1-per-cent. 
solution or combined with platinum chloride as in Hermann's 
solution. I have tried many other solutions for this purpose, 
but found none more suitable. The osmic-acid solution is sprayed 
over the colony in the watch-glass with a pipette and allowed to 
act for several minutes, when it is washed away by repeated 
changes of clean fresh water, allowing the specimens to soak in 
each wash water for some time. Finally they are given a 
weak bath of hydrogen peroxide or potassium ferrocyanide, to 
thoroughly eliminate the acid, and again well washed. This is 
the procedure for Calyptoblastic hydroids, the Gymnoblastic 
may have a little more cavalier treatment. If narcotisation is 
attempted with them it has the effect of causing them to 
gradually shorten the tentacles, and once that has taken place 
they never extend them again while under the influence of the 
narcotic. This being the case the best method is to kill them 
suddenly with an energetic killing agent while fully expanded. 
Some retraction of the tentacles may take place in the killing, 
but to nothing like the extent that would happen if narcotisa- 
tion were attempted. It is unfortunate that mono-bromide of 
camphor is insoluble in sea-water, as I am convinced, from the 
admirable results it gives with Cordylophora and Hydra, that 



PRESERVATION OF THE HYDROIDA. 149 

it would form an excellent narcotiser for this division. Lang's 
fluid is a good killing agent for the Gymnoblastea, and, of course, 
assists staining if carmine is used. Picric acid also answers well ; 
and osmic acid or Hermann's solution if the specimens are not 
too large, otherwise I have found the killing occupy sufficient 
time to permit of considerable contraction. 

Undoubtedly the great difficulty in preparing hydroids for the 
microscope lies in getting clean mounts that is, supposing clean 
mounts are desired and this difficulty becomes augmented with 
material from between tide-marks. The polyparies are generally 
encrusted and overgrown with an olla podrida of marine life, so 
that the mount really becomes a compound object. To me 
this is anything but a drawback, providing, of course, that no 
essential part of the hydroid is masked. On some shores, how- 
ever, the amount of material collected is out of all proportion to 
its interest, and it becomes necessary to subject it to a cleansing 
process. This should be done before narcotising and killing the 
hydroid, otherwise the tentacles are liable to be injured and 
entangled. The polyps withdraw into their calycles during the 
application of the brush, but soon recover from their fright when 
placed in a glass of clean fresh water and allowed to rest quietly 
for a time. 

If staining and mounting fixed material are deferred until a 
more convenient time, it has to be stored in some preservative 
fluid ; formalin at once suggests itself, for which reason I 
wish to utter a word of warning. Formalin is perfectly satis- 
factory for objects that are to be mounted unstained, as they 
will eventually find a permanent home in this medium, but 
personally I have not been successful in staining material that has 
been stored for some months in a 5-per-cent. solution of formalin. 
This, of course, may be due to some error peculiar to myself, but 
I would offer this warning to inexperienced workers. If time 
and facilities allow I would strongly advise the beginner to stain 
straight away, and if unable to mount, then store the stained 
material in 70-per-cent. alcohol. Tailing this, I think it prefer- 
able to store those hydroids destined for staining in 70-per-cent. 
alcohol. In storing avoid the error of putting too many into one 
tube ; small tubes with a few in each are very much better than 
a heterogeneous collection of species in a large tube or bottle. 

The microscopist will doubtless have his own pet stain or stains, 



150 G. T. HARKIS ON THE COLLECTION AND 

and as a good general stain is all that is required for systematic 
work it does not much matter which is used. I have used 
principally para-carmine, carmalum and haemalum of Mayer's 
formulae; the last of which I prefer on account of its better 
visual properties, also because it stains exceptionally well objects 
that have been fixed with osmic acid. I may here mention that 
haeniatoxylin has been regarded by some workers as a fugitive 
stain ; why, I am unable to discover. I attempted to bleach 
some slides that had been over-stained by exposing them for some 
months in a window with a south aspect, and at the end of that 
time withdrew them as hopelessly permanent. They should have 
faded, according to all the authorities, but much to my disgust 
they did not. 

For unstained objects I use excavated slips, and a 2^-per-cent. 
solution of formalin. A ring of old, fairly thick gold size is run 
round the edge of the hollow and allowed to become nearly dry, at 
least dry enough to retain the impression of a scratch made with 
a needle. The selected portion of the hydroid colony is placed in 
the cell, and 2|-per-cent. formalin solution added until a full cell 
with a convex surface to the fluid is obtained. The cover-glass is 
then placed in position, expelling the superfluous formalin. Under 
a mounting microscope, with a strong blunt needle, the cover- 
glass is pressed into intimate contact with the ring of gold size, 
until it can be seen that no lacunae exist between it and the cover- 
glass. The extraneous formalin is now removed and the slide 
allowed to dry, when several rings of gold size may be applied. 
Slides so prepared have attained the comparative antiquity of 
sixteen or eighteen years without showing any deterioration. 

As this paper has been prepared with the object of placing 
practical information before those desirous of devoting some 
attention to our hydroid fauna, it may not be considered alien to 
the subject if I refer briefly to various localities of which I have 
personal knowledge, from collecting more or less frequently in 
them ; merely premising that my acquaintance with them as 
collecting-grounds has been more by accident than design, and I 
have no wish to suggest that they are any more desirable from 
the collector's point of view than numbers of others unknown to 
me. In North Wales my collecting-stations have been Llandudno, 
Menai Straits, Criccieth and Barmouth. Llandudno and Criccieth 
are excellent grounds. The rocks at I4andud.no under the Great 



PRESERVATION OF THE HYJDROIDA. 151 

Orme afford plenty of work at low tide, but rock-pools are 
practically non-existent ; I have taken many good northern 
species from the under-sides of the boulders strewn about. 
Criccieth is a capital ground ; the rocks on the shore at the foot 
of the Castle Hill repay the most ample attention, yielding many 
and good species. A short distance from Criccieth are the Black 
Rock caves, which are really a paradise for the shore collector, 
but are only accessible at low tide. The Menai Straits, also, have 
good collecting-spots on the rocks at the Suspension and Tubular 
bridges, but the drawback to work thereabouts is the swiftness of 
the tide, which makes boating difficult and risky unless accom- 
panied by a local boatman. Pennington collected many species 
between the two bridges. Staithes, in Yorkshire, has a good 
shore for collecting, as the rock-pools are ample. Coming now to 
Devonshire, with whose shores I have intimate acquaintance, we 
reach ground made classic by the labours of Gosse, Hincks, 
Allman, Kingsley, Montagu and many others. Ilfracombe, in 
North Devon, has the advantage of clear rock-pools, in places an 
almost vertical rise and fall of tide, and excellent boating and 
dredging. As it has received its meed of praise at the hands of 
such authorities as Hincks and Gosse, not to mention Lewes, it 
may be considered sufficiently hall-marked. Torquay, Gosse's 
home and hunting-ground par excellence, is indubitably an ideal 
district ; I know no better. The collecting at the Corbon's Head 
alone will occupy a long holiday, and the coast under Livermead, 
Kingsley 's one-time residence, is honeycombed with charming 
rock- pools full of hydroid life. At Brixham one gets in touch 
with a tiawling district, and plenty of chances occur of going 
over trawl refuse. In East Devon, from Exmouth to Sidmouth, 
the naturalist has to set a watch on his lips, for the combination 
of excellent rock-pools and cliffs of Keuper marl is more than the 
average shore collector can bear unmurmuringly. At the same 
time, the fauna of these rock-pools is both luxuriant and diversi- 
fied ; and one has to remember that it was principally in East 
Devon that Hincks collected both hydroids and Polyzoa. 

I would conclude with an apology for the extremely elementary 
nature of this paper. It is a mere account of personal methods, 
offered to the inexperienced in the hope of smoothing away some 
of those preliminary difficulties that appear to be " commensal " 
with the early days of all new subjects. 



152 g. t. harris on the collection and 

Notes on Some Species of Hydroida, principally intended 
for Purposes of Identification. 

Clava multieomis. 

The polypites in this species are scattered, not grouped as in 
the next. 

Clava squamata. 

Polypites in groups, clustered, gonophores in dense clusters at 
base of tentacles. 

Clava cornea. 

Clusters of polypites much smaller than in C. squamata, gono- 
phores smaller and less densely clustered. The two species are 
closely allied, and Dr. T. S. Wright considered cornea a variety 
of squamata. 

Podocoryne areolata. 

Apparently a rare species, as Hincks only records it from three 
localities. It is easily distinguished by the sessile gonophores 
being borne on the chitinous expansion of the stolon. 

Coryne vaginata. 

The common species of the south coast, and may be recognised 
principally by the cup-like membranous expansion of the polypary. 
It is essentially a rock-pool species. 

Coryne pusilla. 

In this species the tentacles are " more truly whorled than in 
any other form of Coryne " (T. H.). The polypites are linear in 
shape, and "of about equal size from one extremity to the other " 
(T. H.). The only specimen I have ever had was found in some 
material sent from Marazion. 

Eudendrium ramosum. 

The height given for this species by Hincks is "about 
6 inches," but it appears to become dwarfed as it nears a littoral 
habitat. 

Eudendrium insigne. 

In the absence of gonophores the specific name can only be 
given with considerable hesitation. Hincks states its habitat 



PRESERVATION OF THE HYDROIDA. 153 

"to be between tide marks on the south coast, and mentions 
a circular groove near the base of the body as a means of 
identification. 

Perigonimus sessilis. 

The only species with ringed coenosarc. The polyp not dilated 
underneath the tentacles. 

Bougainvillea muscus. 

Allman distinguishes this species by its small, habit and the 
fact that its stems consist of a single tube, instead of being 
composed of several tubes coalesced into one. The records for 
this species seem to be very scanty. 

Clytia Johnstoni. 

The pedicel in this species is usually ringed at the top and at 
the bottom, being smooth in the middle portion. Some specimens 
are, however, more or less ringed throughout. 

Obelia geniculata. 

This species is readily distinguished by the projections sup- 
porting the ringed pedicels bearing the hydrotheca. 

Campanularia neglecta. 

The margin of the calycle in this species is crenulate. This 
can only be seen with difficulty, as it is so readily damaged. 

Halecium Beanii. 

It may be easily identified when bearing female capsules by 
their distinctive shape and the short tubular orifice in the middle 
of the capsule. 

Sertularia filicula. 

This hydroid varies in the position of the calvcles on the stem, 
some being placed oppositely, and some more or less alternately. 
It may be distinguished by the single erect calycle in the axils 
of the branches. It is a deep-water species (20 fathoms), and 
more especially a northern species. Hincks never met with it 
in Devon or Cornwall, so its occurrence in rock-pools at Sidmouth 
is somewhat noteworthy. 

Jourx. Q. M. C, Series II. No. 73. 11 



154 G. T. HARRIS, COLLECTION AND PRESERVATION OF THE HYDROIDA_ 

Plumularia pirmata. 

The Plumulariidae are somewhat difficult for the beginner to> 
separate, owing to the superficial resemblance of one species with 
another. The most -trustworthy means of separating the species 
is by a careful observance of the nematophores and distances of 
the calycles. In P. pinnata the nematophores are very minute, 
and lack the pronounced calycle present in other species, and. 
are one below each hydrotheca. The gonothecae also, when 
present, help materially in distinguishing the various species. 
In the present species they are ovate, with spinous projections 
on the top. 

Plumularia setacea. 

It somewhat resembles the former species, but the nema- 
tophores are very different, being of superior size and differing in 
number. The gonothecae are quite different, being flask-shaped ; 
their axillary position also is an aid to diagnosis. 

Plumularia echinulata. 

In this species the pinnae have an unmistakable arched form 
which does not occur in the others. The nematophores are 
smaller than in P. setacea, and one nearly always occurs in the 
axils of the pinnae. The gonothecae, however, when present 
readily determine the species. 

Plumularia similis. 

This appears to be very near the former species (P. echinulata), 
but the gonothecae are totally dissimilar, being without the 
spinous projections. 

Plumularia halecoides. 

A minute species, and easily overlooked, The polypites have- 
been compared to an hour-glass in shape. The gonothecae are 
transversely ribbed. Nematophores very minute and difficult to 
detect. 

[The above notes are intended for use with a series of slides 
presented to the Cabinet by Mr. G. T. Harris.] 



Journ. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 73, November 1913. 



155 



THE MINUTE STRUCTURE OF COSCINODISCUS ASTER. 
OMPHALUS AND OF THE TWO SPECIES OF 
PLEUROSIGMA, P. ANGULATUM AND P. BALTICUM 

By T. A. O'Donohoe. 

{Read May 28th, 1913.) 

Plate 14. 

In preparing this paper it was, at first, my intention to refer in 
no way to the work of others, of which, in fact, I had very little 
knowledge. It has, however, been pointed out to me that it is 
desirable to mention previous researches, in order to enable the 
reader to compare these more easily with my own. Happily 
Mr. E. M. Nelson gives a brief summary of his work on the 
valve of Pleurosigma in a note read at the Club on January 
28th, 1913 (Journ. Q. M. C, vol xii., p. 98). This note is 
therefore easily accessible to all my readers, and any further 
reference to it by me would be unnecessary. I regret I cannot 
so easily dispose of the observations of Mr. T. F. Smith, who 
has for many years devoted much time and thought to the 
structure of diatoms, and who has so recently as August 1911 
and October 1912 contributed to Knowledge two papers on this 
much-discussed subject, entitled " The True Structure of the 
Diatom Valve." These papers contain very many photo- 
micrographs, of which several are excellent. I very much 
regret, however, that I cannot agree with what I must call 
his heterodox views. In his own words, "The points desired to 
be driven home in the present article are that diatom structure, 
consists of neither beads nor perforations as commonly under- 
stood " (page 291). 

Speaking of Pleurosigma for mosum, he says: " It appears to 
consist of a series of chains, as it w-ere, formed of short bars or 
fibrils of silex, arranged lengthways on the valve. They run in 
pairs, parallel, each pair having larger and narrower interspaces 
between them in regular succession, and so placed that the larger 
interspaces are set obliquely to the corresponding interspaces 
between the other pairs both above and below." A few lines 
farther on he tells us that " his theory is this, that what we see 
in the Pleurosigma valve when sound is not the structure at 
all, but simply a collection of focal images thrown from the other 



156 T. a. o'donohoe on the minute 

layer upon the one nearest the eye, just as a picture is thrown 
from the optical lantern upon a canvas screen. The fibrils or 
grating is the real structure, of which the texture is concealed, 
even as that of the canvas screen is concealed by the picture." 
So much for this new theory. We can consider only a few of 
its points. The figures given on page 289 are, we are told, 
photomicrographs of the two separated membranes of a valve of 
Pleurosigma angulatum. If two really good photographs were 
taken of these two membranes at about 4,000 diameters, they 
would, in my opinion, make an end of Mr. Smith's theory, but 
instead of giving his readers two such images, which would be 
extremely interesting and valuable, he gives them a great 
number of outers ides and innersides which, he tells us, do not 
show the structure at all, and are therefore of very little value. 
Indeed, I may say for myself that I attach little or no value to 
interpretations of fine diatomic structure other than those of 
thoroughly separated single membranes. Of these only can we 
speak with a fair degree of certainty. 

Turning now to page 331, we find that Mr. Smith says : " Fig. 
14 is from an innerside of another valve (of P. formosum), the 
first ever seen and taken, showing the fracture through un- 
doubted perforations," and Mr. Nelson, being called to his aid, 
testifies that " Mr. Smith has found this fracture, had shown it 
to him, and that at any rate the fracture did run through the 
holes." So, too, Mr. Smith cites the testimony of Dr. Dallinger, 
who says : " In Plate I. fig. 1 (Carpenter on the Microscope) we 
have a photograph of his showing the inside of a valve of 
Pleurosigma angulatum magnified 1,750 diameters, exhibiting 
the " postage-stamp fracture." The postage-stamp fracture is, 
as everybody knows, a fracture through the holes, so that we 
have these two great authorities testifying to the fact that these 
photographs of Mr. Smith show fractures through holes, or, as 
Mr. Smith calls them, undoubted perforations. His theory being 
that there are neither holes nor beads in the valve of a 
Pleurosigma, does he now repudiate these photographs and 
these testimonies'? He speaks of his fibrils forming interspaces, 
chains and gratings, and it would be interesting to have his 
definitions of these terms. Can there be chains or gratings 
without intervening spaces, i.e. holes or perforations ? 

Fig. 18, page 333, " The innerside of Pleurosigma angulatum 

X 3,770," by no means a sharp image, shows, nevertheless, holes 

galore to any one who is not blind or unwilling to see them. 



STRUCTURE OF C0SC1N0DISCUS AsTEROMPHALUS, ETC. 157 

Mr. Smith's second paper (October 1912) I cannot touch : the 
exigencies of space forbid. 

I am indebted to two members of the Club for the loan of two 
slides realgar mounts which have enabled me to study the 
minute structure of Pleurosigma angulatum and Pleurosigma 
balticiua. Having taken several photographs from a slide lent 
me by my friend Mr. Bruce Capell, I showed some of them to 
our Secretary and Editor, and the latter informed me that 
Mr. Nelson was engaged more or less on the same subject, and 
suggested that I should send him copies of my photographs. 
This suggestion I fell in with the more readily inasmuch as it 
would give me the benefit of any adverse criticism which Mr. 
Nelson might feel himself called upon to make. To elicit this I 
wrote on the back of each a brief interpretation of the structure, 
and in one case in which I was much puzzled I placed a note of 
interrogation. With his usual kindness and urbanity, Mr. Nelson 
gave the desired information, but instead of adverse criticism he 
sent me two slides of great historic as well as intrinsic value. 
From these I have been enabled to make some photographs 
which confirm the results already obtained from the slide belong- 
ing to Mr. Bruce Capell. 

Coming now to my immediate subject, my readers are, no 
doubt, aware that Dr. Van Heurck tells us that a diatom valve 
consists of two membranes and of an intermediate laver which he 
calls a septum, and that it is this latter layer which contains the 
cavities or perforations. In my opinion this definition connotes 
at once too much and too little : too much by giving the valve 
three layers, and too little by confining the cavities to the septum 
only. In the three valves which we are about to consider, I find 
only two layers or membranes, each of which has its own perfora- 
tions. We will, in the first place, consider the structure of 
C oscinodiscus asteromphalus. The photographs are taken from 
some of my own mounts in styrax. Of course I am aware that 
this valve was very ably and fully treated recently elsewhere by 
Dr. Butcher (Journ. R. M. S. 1911, p. 722), but my chief object 
in bringing it before you now is to determine, if we can, which is 
the correct image, the black dot or the white dot. [Here Mr. 
O'Donohoe illustrated his remarks by photographs projected on 
the screen.] The black- and white-dot images now thrown on the 
screen have been taken direct at a magnification of 4,000 
diameters, and to my mind it seems perfectly obvious that two 
images so utterly unlike one another cannot both be correct 



158 T. a. o'donohoe on the minute 

representations of the same structure. The next two slides show 
the inner membrane projecting beyond the outer one, and on 
examining the edge of the fracture it becomes at once evident 
that what is called the eye-spot is a comparatively large 
perforation. This membrane also shows considerable thickness. 
I have been able to find a small fragment in which the outer 
membrane projects a little beyond the inner layer. This is seen 
by the fact that the silex of the projecting part appears white. 
It should now be noted that this white silex is sharply defined at 
the edge, that this edge shows hardly any thickness, and that the 
perforations are represented by black dots. The next image has 
been obtained by making no other alteration than that of raising 
the objective until the white dots appeared. On examining this 
image we find the white silex has become black, and the edge of 
the fracture which was so well defined in the black-dot picture is 
now so blurred and fogged as to have become invisible. We have 
next two fragments of Pleurosigma angulatum in juxtaposition, 
showing respectively the black and white dots. The black dot 
image gives the "postage-stamp" fracture well defined in white 
silex, whereas the broken edge in the other fragment is black, 
out of focus and blurred. We are therefore justified, I think, 
in relegating the white-dot images of diatom structure to the 
abode of Mr. Nelson's ghosts. Here, methinks, I hear the tyro 
in microscopy cry out, " If that be so, why do we meet with 
so many white-dot images in the books which are written for 
our guidance ? " I prefer to let the writers of these books 
answer for themselves. Mr. Pringle, in Practical Photomicro- 
graphy, 1890, page 173, writes: "In spite of all these details, 
A. pellucida is child's play to photograph in comparison with 
such tests as Pleurosigma angulatum, Surirella gemma and 
Navicula rhomboides by axial light and to show ' black dots. 
Pleurosigma angulatum in white areoles, or Navicula rhomboides 
in squares, with a special disc in the condenser, is infinitely 
easier than the same in black dots." 

Let us turn now to Plates III. and IV. of Dr. Spitta's Photo- 
micrography (1899). What do we find? White-dot images of 
all his diatomic tests. Not one black-dot image ! He has, no 
doubt, some good reason for this, and turning to page 138 we 
find it. Writing about the photography of Pleurosigma 
angulatum, Dr. Spitta says : " It has two principal planes of 
focus, and much difference of opinion exists as to which is the 
correct one. The last picture taken by Dr. Van Heurck with 



STRUCTURE OF COSCINODISCUS ASTEROMPHALUS, ETC. 159 

the new Zeiss N.A. 1*6 objective, and the attendant para- 
phernalia, seems to show that after all the black dot is more 
^correct than the white one. As before stated, the white one 
is the easiest to photograph, for the black dot seems never to 
be sufficiently defined to look as sharp as we should like it." 

For the sake of the aforesaid tyro I will here quote a little 
advice which Mr. Nelson gave me eight years ago (I began 
photomicrography very late in life) on the white dot. Among 
several black-dot photographs which I sent him, and which he 
was kind enough to praise, there was a white-dot Isthmia 
nervosa of which he said : ' : I think the Isthmia would be better 
with black-dot focus ; this white-dot focus is an out-of -focus 
ghost. It is much easier to get than a correct picture, and on 
that account it seems to be a favourite with some photo- 
graphers ; but any one really interested in the work should aim 
At something higher. Of course, with very fine structures, a 
white dot is all that can be obtained with our present lenses." 
I thought then, and still think, that this was the kind of 
mentor who would always command and receive the highest 
respect. 

We come now to Pleurosigma angulatum, of which a black-dot 
image x 3,700 is thrown on the screen. The next picture on the 
screen shows a fractured valve which has been denuded of a part 
of its outer membrane. The next image shows this outer mem- 
brane x 2,000 broken up into fragments so minute that the 
particles of silex have in some instances only one, two, three or 
four holes shown as black round dots ; this outer membrane is so 
thin that the silex is almost invisible, and in this respect differs 
very much from the inner membrane, whose image x 2,000 is 
now thrown on the screen. I do not, however, discern any 
difference between the holes in the two membranes. 

Finally, we have to consider the structure of Pleurosigma 
balticum. This, because of its convexity and thickness, is difficult 
to photograph, and yet more difficult to understand. I am 
illustrating its structure by showing you fifteen different photo- 
graphs, each of which I must describe very briefly ; but before 
doing so, let me define the word " fibril " : a fine filament of silex 
which contains holes in a row like a string of beads ; it may 
be long or short. This definition differs altogether from that 
which Mr. T. F. Smith gives to the same word. 

The first slide shows the ordinary valve with Van Heurck's 
canaliculi x 1,500. 



160 T. A. O'DONOHOE ON COSCINOD1SCUS ASTEROMPHALUS, ETC. 

The second slide shows the round black clots of the inner 
membrane near the nodule, where the outer membrane has been 
rubbed off (PI. 14, fig. 1). The third slide shows an impression 
of the greater part of a valve caused by the adhesion of the outer 
membrane to the slip. 

The fourth slide shows a similar adhesion to the cover-glass, 
as well as the valve from which the outer membrane was torn. 
The fifth shows the same x 1,000. 

The sixth slide shows fine hair-like bent fibrils breaking away 
from the valve. 

The seventh shows a part of the same valve x 2,000, on which 
four fibrils of the inner membrane are visible. 

The eighth is an image which puzzled me, and Mr. Nelson 
kindly explained it thus : " This shows an upper bar crossing a 
hole. It also shows the transverse girder work wonderfully 
clearly" (PI. 14, fig. 2). The ninth slide shows the structure of 
the inner membrane to be similar to the last, but this and the 
three next following photographs were taken from Mr. Nelson's 
slide. 

The tenth shows the outer membrane breaking up into fibrils, 
and sometimes even into isolated clots (PI. 14, fig. 3). 

The eleventh and twelfth show continuations of the tenth. 
The thirteenth shows the structure of the fibrils very well (PI. 14, 
fig. 4). The fourteenth and fifteenth show the kind of structure 
which is incorrectly taken for squares, but a glance at one of 
the single fibrils causes the optical illusion to vanish. 

In Pleurosigma balticum the fibrils run parallel with the raphe, 
whereas in Pleurosigma angtdatum they seem to run obliquely to 
the raphe, and this, it seems to me, is the chief difference in the 
minute structure of the two valves. 

Description of Plate 14. 

Fig. 1. P. balticum, X 1,750. Showing the structure of the 
inner membrane when the outer has been rubbed off. 

,, 2. P. balticum, x 2,000. Inner membrane, showing the 
holes crossed by very fine bars of silex. 

3. P. balticum, x 2,000. Fibrils, photographed from Mr. 
Nelson's slide. 

,, 4. P. balticum, x 1,250. Fibrils. 

Journ. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 73, November 1912. 



Journ. Q.M.C. 



Ser. 2, Vol. XII , PI. 14 




1 

ill 

ll III 

will 



I 



.Hi! 



! 



Pliilli 



.: 

I 

it: 



!!i 





t 

III* 



Fig. 1. 



Fig. 3. 




Fig-. 



Fig. 2. 
Photomicrogr. T. A. OD. 

Structure of Pleurosigma balticum. 



1G1 



LAGENAE OF THE SOUTH-WEST PACIFIC OCEAN.. 

(SUPPLEMENTARY PAPER.) 
By Henry Sidebottom. 

{Read June 24/7/, 1913.) 
Plates 15-18. 

INTRODUCTION. 

The Lagenae dealt with in this supplementary paper were- 
arranged by the late Mr. Thornhill on nine slides, each of which 
is divided into one hundred squares. Nearly every square is 
occupied, with the exception of some on the last slide. The 
number of specimens exceeds twelve thousand. In the material 
for mv first paper the number of specimens of Lagenae exceeded 
six thousand, thus making a grand total of over eighteen thousand. 
For reasons stated in my former Introduction, it has not always 
been possible to give the locality at which specimens were found. 

The series dealt with now is on three sets of slides, Nos. 1-4 A 
being Penguin gatherings, Nos. 1-3 b Penguin and Dart gatherings 
combined and Nos. 1,2 c those on which Mr. Thornhill had just 
begun to bring together specimens arranged according to a system 
he had hoped to carry out. 

The specimens of Lagenae on the three sets of slides were not 
arranged in sequence with each other, so that the work has 
proved more laborious than that of my first report. 

The division of the keel, which occurs in a good many tests 
and in more than one species, adds to the difficulty of identifica- 
tion, and it is easy to be misled by it. The same may be said 
of some of the markings on the faces of the test, which have 
hitherto been considered as specific characters. 

Again I must acknowledge the kindness of Mr. Millett, whose 
advice I have always found most valuable and freely given. My 
thanks are due to Mr. Wright, of Belfast, to Prof. Hickson, 
of the University of Manchester, for kind assistance, and also 
to Mr. Earland for bringing these papers before the Quekett 
Microscopical Club and examining specimens for me in order to- 



162 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 

find out the nature of certain markings. Lastly, as regards the 
text, I wish to acknowledge my indebtedness to my wife for her 
assistance in rendering my descriptions more concise. 



H.M.S. " Penguin." S.W. Pacific. 1897. 



No. 


Statioi 


1. 


939. 


2. 


940. 


3. 


941. 


4. 


943. 


5. 


945. 


6. 


947. 


7. 


949. 


8. 


952. 


9. 


954. 


10. 


955. 


11. 


956. 



23. 



f 2] 
U7i 



Lat. & Long. 

f 18-29' S. 
\ 178-38' E. 
/ 18-57' S. 
U 79-04' 
/ 18-43' 

U 78-51' 
/ 19-21' 
(.179-30' 

21-47' 
179-25' 
/ 22-49' 
\ 179-20' 
/ 23-44' 
\ 179-09' 
/ 25-52' 
\ 178-47' E. 

f 26-57' 8. 
1 178-35' 

f 27-46' 
\ 178-29' 

/ 29-17' 
i 177-17' 



E. 

8. 
E. 

S. 
E. 

S. 
E. 

S. 
E. 

S. 
E. 

S. 



E. 

S. 
E. 

8. 
E. 



H.M.S. "Pen 



No. Station. 



4. 



24. 



12. 



18. 



21. 



24. 



25. 



27. 



Lat. 

r 33- 

\157- 

r 33- 

\158- 
/ 33- 

U60- 

f 33- 
\161- 

/ 33- 

\162- 

f 33 
(163 

/ 33- 
V163- 

f 33- 
U64 

/ 33- 
\164 

f 34 

\165- 



& Long. 



53' S. 




29' E. 




50' 8. 




47' E. 




48' 8. 




2' E. 




56' S. 




13' E. 




56' 7" 


S 


33' 


E 


56' 6" 


S 


20' 


E 


57' 8. 




56' E. 




58' S. 




37' E. 




58' 5" 


S 


55' 


E 


0' 6" 


S 


37' 


E 



GUIN. 

Fms. 

2,578. 
2,338. 
1.190. 

98S. 

498. 

575. 

603. 
1,073. 
1,653. 
1.676. 



Fms. 


No. 


1,122. 


12. 


1,092. 


13. 


1,360. 


14. 


1,420. 


15. 


2,043. 


16. 


1,948. 


17. 


1,903. 


18. 


2,183. 


19. 


2,318. 


20. 


1,803. 


21. 


2,050. 


22. 



Station. 
959. 

961. 

964. 

974. 

975. 

976. 

986. 

987. 

996. 

998. 

1,003. 



Lat. & Long. 

f 31-39' S. 
\ 176-49' E. 

/ 33-00' 8. 

\176-16' E. 

/ 34-52' 8. 

(175-34' E. 

f 35-01' S. 
\171-37' E. 

f 35-23' S. 
1 170-34' E. 
/ 36-09' S. 

^ 169-20' E. 

f 36-30' S. 
\168-11' E. 

f 37-10' S. 
1 166-30' E. 

/ 37-47' S. 
\ 164-40' E. 

f 38-24' S. 

1 163-15' E. 

/ 4305' 8. 

(148-39' E. 



S.W. Pacific. 1898. 



No. 



25. 1 



Station. 
35. 

41. 

44. 

75. 



26. 



I 



27. 



28. 



83. 
85. 
86. 
87. 



Lat. & Long. 

/ 34-19' 8. 

\168-6' E. 

/ 34-20' S. 

\ 168-28' E. 

/ 34-22' 8. 

\17019' E. 

f 36-21' 8. 

\176-44' E. 

f 36-3' S. 

\ 17855' E. 

/ 34-33' S. 

\. 178-15' W. 



f 32-56' S. 
\ 176-49' W. 

S. 

w. 

/ 31-28' S. 
{ 171-5' W. 



/ 3216' 
\175-54' 



Fms. 
2,210. 

2,086. 

917. 

796. 

994. 
1,298. 
1,207. 

822. 

735. 
2,182. 
1,611. 



Fms. 

828. 

1,191. 
979. 

832. 
1,389. 

4,278. 

3,360. 
3,220. 
3,100. 



HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 163 



No" 


Station 


29. 


93. 




90. 


^in 


94. 


ou.- 


95. 




96. 


31. 


98. 


32. 


143. 



No. 

37. 

38. 



39. 



40. 



Station. 
140. 

70. 

181. 

182. 

188. 

191. 

192. 

393. 

429. 

480. 



Lat. & Long. 


Fins. 


f 26-38' s. 
\17417' W. 


2,420. 


f 2917' S. 
\ 175-11' W. 


3,105. 


/ 25-53' S. 
U"46' W. 


2,775. 


f 23-24' S. 
\ 173-40' W. 


3,205. 


f 22-14' S. 
1 17329' W. 


3,420. 


/ 21-8' S. 
\ 174-7' W. 


2,115. 


f 23-15' 8. 
\175-32' E. 


2,351. 
1 


H.M.S. " 


Penguin 


Lat. & Long. 


Fms. 


f 10-57' S. 
\162-21' E. 


508. 


f 23-17' 8. 
\ 154-33' E. 


470. 


/ 11-42' 8. 
U75-51' W. 


2,335. 


f 11-09' 8. 
\ 175 -36' W. 


1,992. 


f 9-41' S. 
\ 174-37' W. 


2,290. 


/ 8-57' 8. 
V 174-03' W. 


2,606. 


f 8-36' S. 
\ 173-51' W. 


2,712. 


/ 3-51' N. 
\ 164-13' W. 


2,330. 


/ 4-55' N. 
\ 160-54' W. 


1,701. 


/ 5-10' N. 
\ 160-15' W. 


2,033. 



No. Station. 



f 



33. 



34. 



35. 



36. 



14S. 



149. 



151. 



156. 



157. 



167. 



169. 



172. 



Lat. <fc Long. 

f 261' 8. 

\ 172-56' E. 

f 26-38' 8. 

\172-26' E. 

/ 27-55' 8. 

\171-22' E. 

f 29-35' 8. 

\ 168-51' E. 

f 29-42' 8. 
\ 168-51' 
/ 30-29' 
\ 166-16' 

f 30-57' 
\ 160-52' 

T 31-18' 
\ 163-46' 



E. 

8. 
E. 
8. 
E. 
8. 
E. 



S.W. Pacific. 



No. 



40. 



41.x 



Station. 
482. 

487. 

488. 

498. 

499. 
502. 
503. 
505. 
506. 



Lat. & Long. 

/ 6-15' N. 
\ 160-36' W. 

/ 7-25' N. 
\ 160-59' W. 

f 7-47' N. 
\ 160-45' W. 

/ 8-47' X. 
\ 159-45' W. 

f 904' N. 
\ 159-32' W. 

/ 9-43' N. 
\ 159-07' W. 

f 1004' N. 
1 158-53' W. 

f 10-43' N. 
\ 158-30' W. 

/ 11-01' N. 
X 158-21' W. 



Fms. 
2,428. 

2,070. 

1,632. 

1,269. 

1,446. 

1,819. 

1,557. 

1,010. 



Fms. 

1,861. 
2,501. 
2,573. 
2,588. 

2,579. 
2,758. 

2,800. 
2,938. 
2,863. 



Ko. Station. 

f 

No date 

42. 



Lat. k. Long. 

2415' 8. 
E. 

S. 
E. 

/ 24-36' 8. 
\15332' E. 



/ 24- 1 
\153-1 
/ 24-34' 
\ 153-32' 



H.M.S. "Dart." 

Fms. 
328. 

478. 

392. 



No. Station. Lat. <fc Long. 


Fms 


d , / 19. f 29-22' S. 
^\(14.5.97.)\153-51' E. 


465 


44.{(16.1.97.){ 1 ^; 


481 



164 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 

Family LAGENIDAE. 

Sub-family Lageninae. 

Lagena Walker and Boys. 

Lagena globosa Montagu sp. (PI. 15, figs. 1-3). 

Serpula (Lagena) laevis globosa Walker and Boys, 1784, Test. Min. r 

p. 3, pi. 1, fig. 8. 
Vermiculum globosam Montagu, 1803, Test. Brit., p. 523. 

Very numerous and of varying size and shape. The orifice 
and internal tube are subject to great variation. Locality : 
Many .stations. 

PL 15, fig. 1. The orifice is small and somewhat hooded, and 
the test often inclined to be apiculate. Locality : Many stations. 
Rare. 

PI. 15, fig. 2. An elongate variety. Locality: Uncertain. 

Only one found. 

PI. 15, fig. 3. An interesting variation, the body of the test 
being partly clear and partly opaque. The curiously produced,, 
flattened mouth, which appears to be divided or pinched in at the 
centre, points to its being allied to the one figured + PI. 14, fig. 2.* 
The entosolenian tube is absent. t Locality : Nos. 21-26, 34, 38, 
42, 44. 

+ P1. 14, fig. 2. Locality: Uncertain. 

+ P1. 14, fig. 4. The slightly elongated form predominates. 
Locality : Many stations, including Nos. 6, 8 ; after No. 22 only 
at one or two stations. 

+ P1. 14, fig. 5. This compressed variety of the above is found 
sparingly at a few stations, but tests that are much more com- 
pressed, and pointed towards the aperture, are frequent. 

Lagena globosa Montagu sp. single and bilocular form. 

Lagena globosa Montagu sp. single and bilocular form, Sidebottom, 
1912, Journ. Q. M. C, p. 380, pi. 14, figs. 7, 8, 9. 

Locality : Many stations up to No. 19, also at Nos. 33, 43, 44. 

* The "4*" denotes that the reference is to " Lagenae of the South- 
West Pacific Ocean " (Journal Quekttt Microscopical Club, 1912, ser. 2, 
vol. xi., pp. 375-434, pis. 14-21). 

f The numbers throughout this paper refer to my charts on pp. 162, 163, 
where will be found the official numbers of the stations, with other 
particulars. 



HENRY SIDEBOTTOM OX LAGENAE OF THE SOUTH-WEST PACIFIC. 165 

Lagena globosa Montagu sp. var. maculata Sidebottom. 

Lagena globosa Montagu sp. var. maculata, Sidebottom, 1912, 
Journ. Q.M.C. p. 380, pi. 14, figs. 10, 11. 

Locality : Nos. 5 9. 

Lagena globosa Montagu sp. var. emaciata Reuss. 

Lagena emaciata Reuss, 1862 (1863), p. 319, pi. 1, fig. 9. 
Lagena globosa Montagu sp. var. emaciata (Reuss) Sidebottom, 
1912, Journ. Q. M. G. p. 381, pi. 14, figs. 13-15. 

Locality : Present at numerous stations throughout the series. 

Lagena apiculata Reuss sp. (PI. 15, fig. 4). 

Oolina apiculata Reuss, 1851, p. 22, pi. 1, fig. 1. 
Lagena apiculata Reuss, 1862 (1863), p. 318, pi. 1, figs. 1, 4-8, 
10, 11. 

PI. 15, fig. 4. A large, solitary specimen. Locality : No. 15. 

+ P1. 14, fig. 16. Always rare. Locality : At Nos. 24, 43, and 
a, few other stations. 

"J" PI. 14, figs. 17, 18. Found at many stations. Locality: 
Chiefly at Nos. 2, 24, 42, 44. 

*P1. 14, figs. 19, 20. The tube in this variation is very 
delicate, and often lies broken inside the test. Locality: Occurs 
at very many stations. 

Lagena apiculata Reuss sp. var. punctulata Sidebottom. 

Lagena apiculata Reuss sp. var. punctulata Sidebottom, 1912, 
Journ. Q.M. C, p. 382, pi. 14, figs. 21-23. 

Locality : Nos. 3, 5-11, 41, 43. 

Lagena longispina Brady (PI. 15, figs. 5, 6). 

Lagena long ispina Brady, 1881, Quart. Journ. Micro. Sci., vol. xxi., 

N.S., p. 61. 
Lagena longispina Brady, 1884, p. 454, pi. 56, figs. 33, 36 ; pi. 59, 

figs. 13, 14. 

As Brady states in the Challenger Report, this is simply a 
variety of L. globosa. It is not unusual for L. globosa to have 
the base of the test roughened or finely spinous. The larger of 



166 HENRY S1DEB0TT0M ON LAGENAE OF THE SOUTH-WEST FACIFICL 

the two specimens figured is so opaque that it is impossible to 
say whether the entosolenian tube is present. Locality : Nos. 5,, 
7, 9, 39-41, 44. 

Lagena ovum Ehrenberg sp. 

Miliola ovum Ehrenberg, 1843, p. 166; 1854, pi. 23, fig. 2; 
pi. 27, fig. 1 ; pi. 29, fig. 45. 

Locality : This unsatisfactory form occurs at many stations, 
but is always rare. See remarks +p. 382. 

Lagena botelliformis Brady (PL 15, figs. 7, 8). 
Lagena botelliformis Brady, 1884, p. 454, pi. 56, tig. 6. 

PI. 15, fig. 7. Only two specimens found. The orifice is phia- 
line, and there is a short internal tube. Locality : No. 44. 

PL 15, fig. 8. This is a very fine example in the apiculate- 
condition. See also +PL 14, fig. 24. Locality: No. 12. 

+ P1. 14, figs. 24, 25. Locality; Many stations. 

**"PL 14, figs. 26-28. Locality: Stations uncertain. 

Lagena laevis Montagu sp. (PL 15, figs. 9, 10). 

Serpula (Lagena) laevis ovalis Walker and Boys, 1784, p. 3, pi. 1,. 

fig. 9. 
Lagena laevis (Walker and Jacob) Williamson, 1848, p. 12, pi. 1, 

figs. 1, 2. 

L, laevis occurs frequently in these gatherings, and the form 
of the test, the decoration of the neck and the position of the- 
internal tube varies. Some are apiculate. In a few instances 
there is an entosolenian tube situated at the base. Locality .- 
Many stations. 

PL 15, fig. 9. The tests are semi-opaque, the short neck is- 
decorated and the internal tube straight. In several instances 
fine spines project at the base. Locality : Nos. 1, 2, 3, and one- 
or two others. 

PL 15, fig. 10. This appears to be a smaller variety of the- 
above. The tests are too opaque for me to make out whether 
the entosolenian tube is present. Some are apiculate and may- 
be L. laevis var. distoma Silvestri. Locality : At a good many 
stations throughout the series. 



HENRY SIDEBOTTOM ON LAGEXAE OF THE SOUTH-WEST PACIFIC. 167 

Lagena laevis Montagu sp. var. distoma Silvestri. 

Lagena laevis (Montagu) Silvestri, 1900, p. 244, pi. 6, figs. 74, 75. 

Examples are rare, but they occur at a fair number of stations.. 
Locality : Chiefly at Nos. 1, 6, 11, 15, 17, 22, 42-44. . 

Lagena gracillima Seguenza sp. 

Amphorina gracilis Costa, 1856, p. 121, p. 11, fig. 11. 
Am ph or ina gracillima Seguenza, 1862, p. 51, pi. 1, fig. 37. 

Eight specimens occur which are all curved. Locality : No. 44. 
Besides these specimens, only two or three others were found. 
Locality : Uncertain. 

Lagena elongata Ehrenberg sp. 
Miliola elongata Ehrenberg, 1854, pi. 25, 1a, fig. 1. 

I do not think these can be separated from L. gracillima 
Seguenza sp., as they appear to pass insensibly from one form to 
the other. Seven specimens occur, also two or three doubtful 
examples. Locality : Six at No. 43, and one at No. 2. 

Lagena aspera Keuss (PI. 15, figs. 11-13). 
Lagena aspera Eeuss, 1861, p. 305, pi. 1, fig. 5. 

Pi. 15, fig. 11. This is in good condition, except that the neck 
is broken. The protuberances, which are arranged in lines, are, 
I think, tubular. Locality : No. 17. 

On another square are two smaller specimens, with very small 
protuberances ; these also have the neck fractured. They appear 
to be a weak form of the above. Locality : Uncertain. 

PI. 15, g. 12. Two specimens only occur ; the one figured is in 
a very opaque condition, the other is clear but much smaller. 
Locality : Nos. 1, 22. 

PI. 15, fig. 13. Three specimens found, the neck being bent to 
one side in each case. It is not unlikely that future investigation 
will reveal a connection between these forms and L. striatopunctata. 
Locality : No. 43. 

There are also two oval tests, which have the protuberances, 
and the lines in which they are arranged, farther apart. The 
protuberances are very minute. Locality : No. 10. 



168 HENRY S1DEB0TT0M ON LAGENAE OF THE SOUTH-WEST PACIFIC. 

Lagena rudis Reuss (PI. 15, fig. 14). 

Lagena rudis Reuss, 1862 (1863), vol. 46, p. 336, pi. 6, fig. 82. 

A single example. The test is opaque and of a faint silvery- 
yellow colour. Locality : No. 24. 

Lagena ampulla-distoma Rymer Jones. 

Lagena vulgaris var. ampulla-distoma Rymer Jones, 1872, p. 63, 
pi. 19, fig. 52. See also + p. 384. 

Locality : Nos. 1, 2, 3, 8, 19, 22, 24, 42, 43. 

Mr. Millett, 1901, p. 6, mentions two other localities for this 
species, besides the Malay Archipelago ; it may therefore be worth 
while to state that I have since recorded it from the coast of 
Delos and Palermo. 

Lagena hispida Reuss (PI. 15, fig. 15). 

Sphaerulae hispidae Soldani, 1798, p. 53, pi. 17, v, x. 

Lagena hispida Reuss, 1858, p. 434. 

Lagena hispida Reuss, 1862 (1863), p. 335, pi. 6, figs. 77-79. 

In one form or another this is found at nearly all the stations. 
There is great variation in size, and shape of the tests, and many 
of the small ones have a long entosolenian tube at the opposite 
end from the neck, so that it is difficult in some cases to say which 
is the right end up. If turned one way, they might be treated as 
apiculate forms. 

PI. 15, fig. 15. The orifice is circular and sunk in a depression. 
The oral end of the test is surrounded by a series of short spines. 
A solitary example. Locality : No. 24. 

* PI. 15, fig. 1. Ten specimens occur. Locality : Nos. 5, 6, 8, 
and a single example at either Nos. 41 or 42. 

Lagena hispida Reuss, compressed form. 

+ P1. 15, fig. 2. Locality: Nos. 1-3, 5-7, 10, 24, 33, 34, 36, 
38 40, 42. 

Lagena hispida Reuss var. tubulata Sidebottom (PI. 15, fig. 16). 

Lagena hispida Reuss var. tubulata Sidebottom, 1912, Joum. 
Q. M. C, p. 385, pi. 15, figs. 3-5. 

PI. 15, fig. 16. Nearly all the smaller tests have their necks 
broken, and a few are very large, as can be judged from the 



HENRY SIDEBOTTOM OX LAGENAE OF THE SOUTH-WEST PACIFIC. 169 

drawing. The largest specimens have the body much clogged by 
exogenous shell-growth, or debris, through which small spines 
often project. Locality : Nos. 17, 19. 24. 25, 35. 36. Always rare. 
+ P1. 15, fig. 5. This variation, which is much more delicate in 
every way. is found at many stations. Locality: Xos. 1-11. 24, 
25. 33, 35, 36. 39. 

Lagena striata d'Orbigny sp. (PL 15. fig. 17). 
Oolina striata d'Orbigny, 1839, p. 21, pi. 5, fig. 12. 

Many examples at numerous stations. They vary remarkably 
both in size and decoration. Many are apiculate. -f- See remark-. 
p. 386. 

PI. 15. fig. 17. In this, the fine costae project at the base. The 
neck is bent to one side, the body of the test is also slightly 
curved. On a square by themselves are fifteen tests which have 
the contour of L. clavata, with the point at which the test begins 
to narrow towards the base sharply angular. Only two are 
marked on the chart. Locality : Nos. 1, 3-5. 7. 8. 12. 17. 21, 24, 
34. 39. 40. 

Lagena (Amphorina) Lyellii Seguenza sp. is found frequently. 
This form may be treated either as L. striata, or L. sulcata in an 
apiculate condition. 

* PI. 15. fig. 6. Twenty-three specimens are on the slide. 
Locality : Nos. 2. 3. 4. 

* PI. 15, fig. 8. Fourteen fine examples occur, and a number 
of smaller ones. Taking the whole series into account they pass 
gradually into L. Lyellii Seguenza. Locality; Nos : 2-12. 15, 17. 
21, 24, 29, 31, 33, 34. 39. 40, 42, 43. 

+ EL 15, fig. 9. Five typical tests are on the slide, but they 
are mixed with others that are not typical, and so the exact 
locality cannot be given with certainty. They were found, how- 
ever, at one or two of the following stations. Locality : ZSTos. 
1, 5, 11, 13. 

On another slide two examples are placed. Locality : 2Sos. 
23. 24. 

Lagena striata d'Orbigny sp. var. tortilis Egger. 

Lagena tortilis Egger, 1893, p. 329, pi. 10, figs. 61-63. 

Two examples only. Locality : Nos. 43. 44. 

Journ. Q. M. C., Series II. No. 73. 12 



170 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC 

Lagena striata d'Orbigny sp. var. striatotubulata Sidebottom. 

Lagena striata d'Orbigny sp. var. striatotubulata Sidebottom,. 
1912, Journ. Q. M. C., p. 387, pi. 15, figs. 11, 12. 

This is well represented. A good many are more or less- 
fractured, otherwise they are clean and fresh-looking. Locality r 
Nos. 4-12, 23, 24, 29, 33, 34, 39, 40. 

Lagena distoma Parker and Jones. 

Lagena laevis var. striata Parker and Jones, 1857, p. 27S, pi. 11, 
fig. 24. 

There is a single large specimen and it agrees with the 
Challenger figure, pi. 58, fig. 11. Locality : No. 2. 

There are about twelve examples which have their sides slightly" 
curved and parallel as in the type. Locality : Uncertain. 

Lagena lineata Williamson sp. 

Entosolenia lineata Williamson, 1848, p. 18, pi. 2, fig. 18. 

Many examples found. Locality : Nos. 1, 2, 4, 5, 9, 10, 13-15, 
17-20, 22, 24, 25, 36, 38, 42-44. 

+ PI. 15, fig. 15. The variety with the costae curved occurs at 
many stations. 

Non-apiculate forms also are present. 

Lagena variata Brady. 

Lagena variata Brady, 1881, Quart. Journ. Micr. Sci., vol. 21,. 

N.S., p. 61. 
Lagena variata Brady, 1884, p. 461, pi. 61, fig. 1. 

Only two typical examples. Locality : Uncertain. 

+ PL 15, fig. 13. The neck of the test is in many cases not so 
long as in the figure referred to. Locality : Nos. 14, 15, 17, 19, 
22, 24, 25, 44. 

Lagena costata Williamson sp. (PI. 15, figs. 18, 19). 

Entosolenia costata Williamson, 1858, p. 9, pi. 1, fig. 18. 

Occurs frequently, typical and otherwise, sometimes apiculate. 
PL 15, fig. 18. This appears to be an elongate form with from. 



HENRY SIDEBOTTOiM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 171 

eight to ten costae. Entosolenian tube straight. Locality : 
Ud certain ; probably No. 22 and a few other stations. 

PI. 15, fig. 19. These appear to be the same, but they have 
only six costae, and occur more frequently. .Nos. 15, 17-20, 23, 
24, 29, 33-36. 

+ P1. 15, fig. 16. Locality: Many stations throughout the 
whole series. 

+ P1. 15, fig. 19. Locality: No. 43. 

Lagena acuticosta Reuss (PI. 15, fig. 20). 
Lagena acuticosta Reuss, 1861, p. 305, pi. 1, fig. 4. 

An unsatisfactory species, for it is linked closely with L. costata 
on the one hand, and L. sulcata on the other. Locality: Many 
stations up to No. 22 ; afterwards extremely rare. 

PI. 15, fig. 20. An odd specimen, probably a very weak form. 
Locality : Uncertain. 

+ PI. 15, fig. 22. Tests similar or nearly so oc^ur, but they are 
not so large. Locality : Nos. 2, 7, and a few other stations. 

Lagena melo d'Orbigny sp. 
Oolina melo d'Orbigny, 1839, p. 20, pi. 5, fig. 9. 

There are several fine typical examples and a few small ores 
on the slide, but as they are mixed with other varieties the 
locality cannot be determined. 

The form with the cross-bars sunk, which is assigned by 
Reuss to L. catenulata Williamson, 1862 (1833), pi. 6, fig. 75, is 
also present. 

Lagena hexagona Williamson sp. (PI. 15, figs. 21-23). 

Entosolenia squamosa var. hexagona Williamson, 1848, p. 20, pi. 2, 
fig. 23. 

Very many beautiful specimens occur ; some are globular, 
others pyriform, with and without necks. The depth and size of 
the mesh var} 7 greatly. 

A few, w^hich I take to be L. geomeirica Reuss, 1862 (1863), 
pi. 5, fig. 74, are exquisite, although the arrangement of their 
cells is not always parallel. The cells are deep, and their sides 
exceedingly delicate. Several have short necks. I have not 
attempted to draw them, as I could not have produced the 



172 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 

desired effect. Locality: Again the mixing of the varieties 
prevents me from giving any definite information. 

There are a few which appear to be the same as the one 
figured by Brady in the Challenger Report, pi. 58, fig. 33, of 
which the angles of the cells tend to become spinous, especially 
at the base of the test. This peculiarity seems to be feebly indi- 
cated in Brady's figure. 

PI. 15, fig. 21. Several of this elegant form occur. Locality : 
Uncertain. 

PI. 15, fig. 22. A globular variety. 

PI. 15, fig. 23. A compressed variation of the above, but of 
smaller size. These two forms are placed together on the slide. 
Locality ; Taking the two forms together they are marked 
Nob. 2-5, 13, 17-20, 44. 

Lagena squamosa Montagu sp. 

Vermiculum sqtiamosum Montagu, 1803, Test. Brit. p. 526, pi. 14, 
%. 2. 

A few only are present. Locality : Uncertain. 

Lagena exsculpta Brady. 

Lagenulina sulcata Terquem, 1876, Anim. sur la Plage de 

Dunkerque, fasc. 2, p. 68, pi. 7, fig. 9. 
Lagena exsculpta Brady, Quart. Journ. Micr. Sri., vol. xxi., N.S., 

p. 61. 
Lagena exsculpta Brady, 1884, p. 467, pi. 58, fig. 1 ; pi. 61, fig. 5. 

Five examples found, and they are compressed. Three of them 
are in poor condition. These latter are not quite typical, as 
the sculptui e becomes irregular at the base. Locality : ISTos. 
37, 39. 

Lagena sulcata Walker and Jacob sp. (PI. 15, figs. 24, 25). 

Serpula (Lagena) striata sulcata rotunda Walker and Boys, 1784, 

p. 2, pi. 1, fig. 6. 
Serpula (Lagena) sulcata Walker and Jacob, 1798, p. 634, pi. 14, 

fig. 5. 

This common foraminifer is well represented. In some the 
body of the test is globular, and in others cylindrical. Apicu- 



HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 173 

late forms also occur. Locality : Nos. 4, 14, 15, 20, 24, 26, 38, 
42-44, and a few others. 

PI. 15, fig. 24. This is closely allied to L. alifera Beuss, 1870, 
p 467. Von Schlicht, 1870, pi. 3, figs. 15, 16, 21, 22. Locality : 
Nos. 3. 10, and two or three others. 

PI. 15, fig. 25. This form, known as L. sulcata var. interrupta 
Williamson, is hardly worthy of a varietal name, as it is not at 
all uncommon for some of the costae or striae, both in L. sulcata 
and L. striata, to be shorter than the others. 

Lagena plumigera Brady (PI. 15, fig. 26). 

Lagena plumigera Brady, 1881, Quart. Journ. Jficr. Sci., vol. 21, 

N.S., p. 62. 
Lagena plumigera Brady, 1884, p. 465, pi. 58, figs. 25, 27. 

Two of the tests are similar to the one figured ; several others 
are smaller and much damaged. Locality : Nos. 1, 2, 43. 

Lagena semilineata Wright (PI. 15, fig. 27). 

Lagena semilineata Wright, 1884-5, App. 9, 1886, p. 320, pl. 26, 
fig. 7. 

Evidently a bold form of L. semilineata. Locality: Three 
examples at Station No. 2. 

Lagena gracilis Williamson. 

Lagena gracilis Williamson, 1848, p. 13, pl. 1, fig. 5.. 

This protean species is found at many stations throughout 
the whole series. All the forms represented in the Challenger 
Report, 1884, appear to be present. No line of demarcation can 
be drawn between this species and apiculate forms of L. sulcata 
and Z. striata ; they are also linked with L. distoma Parker and 
Jones. 

Lagena quinquelatera Brady. 

Lagena quinquelatera Brady, 1881, Quart. Journ. Micr. Sci., vol. 

21, N.S., p. 60. 
Lagena quinquelatera Brady, 1884, p. 484, pl. 61, figs. 15, 16. 

I take this to be a variety of L. gracilis. 
Two specimens only. Locality : No. 2. 



174 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 

Lagena semistriata Williamson. 

Lagena striata var. /? semistriata Williamson, 1848, p. 14, pi. 1, 
figs. 9, 10. 

The great majority are small. Some have the neck bent to 
one side and the body slightly curved. A few are cylindrical and 
others have the contour of L. clavata d'Orbigny. Locality : Nos. 
1, 20-22, 29, 42-44. 

Lagena crenata Parker and Jones var. (PI. 15, fig. 28). 

Lagena crenata Parker and Jones, 1865, p. 420, pi. 18, fig. 4. 

They are not typical, but I think they are best placed under 
the above heading. The projecting parts at the base run partly 
towards its centre as blades. The neck is not decorated. A few 
of the examples are not so slim as the one figured, and have their 
sides slightly convex. Thirteen specimens occur. I cannot give 
all the stations at which they are found, but the following may 
be indicated. Locality : 22, 43. 

Lagena Thornhilli Sidebottom (PI. 15, fig. 29). 

Lagena Thornhilli Sidebottom, 1912, Journ. Q.M.C., p. 390, 
pi. 15, fig. 26. 

They differ slightly from the one figured at the above reference, 
for the upper parts of the wings are joined together so as to 
form a hood, as shown in the figure. In one of the examples 
the three cavities formed by the hood are blocked with exogenous 
shell-growth. 

Four examples occur. Locality : 6, 8, 29. 

Lagena stelligera Brady. 

Lagena stelligera Brady, 1881, Quart. Journ. J/icr. Sci., vol. 21, 

N.S., p. 60. 
Lagena stelligera Brady, 1884, p. 466, pi. 57, figs. 35, 36. 

A good many agree with Brady's Challenger figure, pi. 57, 
fig. 35, but some are more slender, and several are very 
minute. 

See remarks, + pp. 391, 392. Locality : Nos. 5, 14, 17-19, 21, 



HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 175 

22, also Nos. 23, 24, 29, 32, 33, 35, 37, 39-41. From these latter 
stations a few of the " nude " form were obtained. 

* PL 16, fig. 1. In most of the specimens, some of the costae 
-are more prominent than the others, but none of them are "inter- 
rupted," as in the figure referred to. Locality : 10, 22-24, 36, 39. 

+ P1. 16, fig. 2. Numerous examples of this " nude " variety 
are on the slides, some having very long, delicate necks. The 
apiculate portion varies both in width and length. Two very 
large tests were found, and except for the absence of the costae 
they agree well with the Challenger figure, pi. 57, fig. 36. 
Locality : Nos. 2, 3, 5, 12, 19, 23, 24, 29, 32, 33, 35, 36, 38-40. 

+ P1. 16, fig. 3. Locality: Nos. 3-7, 9, 10, 13, 17, 23, 24, 26, 
29, 33 35, 39, 40. 

* PI. 16, fig. 4. Compressed. Nine examples found. Locality: 
Nos. 2, 24. Other stations uncertain. 

Lagena stelligera Brady var. eccentrica Sidebottom (PI. 15, 

fig. 30). 

Lagena stelligera Brady var. eccentrica Sidebottom 1912, Journ. 
Q. M. O., p. 392, pi. 16, figs. 5, 6. 

PI. 15, fig. 30. On this specimen the ridge at the base is 
scarcely perceptible. Two or three only found. Locality: Un- 
certain. 

+ PI. 16, fig. 5. Not typically represented in these gatherings. 

+ P1. 16, fig. 6. The examples generally have the ridge at the 
base carried farther up the side of the test. Locality : Nos. 11, 
14, 37. 

Lagena stelligera Brady var. eccentrica Sidebottom, com- 
pressed form (PL 15, fig. 31). 

This is the compressed form, and some of the specimens from 
No. 43 are in fine condition. Locality : Nos. 10, 13. 14, 19, 20- 
43. Very rare, except at No. 43. 

Lagena striatopunctata Parker and Jones. 

Lagena sulcata var. striatoptmctata Parker and Jones, 1865, 
p. 350, pi. 13, figs. 25-27. 

Various forms are present. Some have the neck bent to one 
.side, others have only a very short neck. The body of the test 



176 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 

also varies greatly, being occasionally almost globular. Locality : 
Nos. 1-3, 22, 24 26, 33, 34, 38, 42, 43. 

Lagena striatopunctata Parker and Jones (?) var. complexa 

Sidebottom. 

Lagena striatopunctata Parker and Jones (?) var. complexa Side- 
bottom, 1912, Journ. Q. M. C, p. 393, pi. 16, fig. 11. 

"*" PL 16, fig. 11. None of the tests are in perfect condition, 
all showing signs of the disintegration mentioned at the above 
reference. Locality : Nos. 7, 9, 24. 

Lagena striatopunctata Parker and Jones var. inaequalis 

Sidebottom. 

Lagena striatopunctata Parker and Jones var. inaequalis Side- 
bottom, 1912, Journ. Q. J/. C, p. 393, pi. 16, fig. 12. 

Three tests are on the slide, but only two belong to this variety. 
Locality : Two of the following, Nos. 4, 10, 11. 

Lagena striatopunctata Parker and Jones var. spiralis Brady. 

Lagena spiralis Brady, 1884, p. 468, pi. 114, fig. 9. 

Locality : Nos. 1-4, 22, 37, 38, 43, 44. Very rare except at 
No. 1. 

Lagena Fieldeniana Brady. 

Lagena Fieldeniana Brady, 1878, Ann. Mag. Nat. Hist. (5) vol. 1. 

p. 434, pi. 20, fig. 4. 
Lagena Fieldeniana Brady, 1884, p. 469, pi. 58, figs. 38, 39. 

A solitary, rather rotund example, of which the neck is broken 
off short. Locality : Uncertain. 

Lagena desmophora Rymer Jones. 

Lagena vulgaris var. desmophora Bymer Jones, 1872, p. 54, 
pi. 19, figs. 23, 24. 

The specimens are typical and in good condition. All are, or 
have been, apiculate. The number of spines at the bate varies 
from one to four. Locality : Nos. 2, 5, 7-11, 13, 33, 40. 



HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 177 

Lagena foveolata Reuss. 

Lagena foveolata Reuss, 1862 (1863), p. 332, pi. 5, fig. 65. 
Lagena No. 25, von Schlicht, 1870, p. 10, pi. 3, fig. 25. 

Three or four only occur. The sculpture of the test is ex- 
ceedingly fine. Locality : No. 43, and one or two other stations 
which are uncertain. 

Lagena foveolata Eeuss var. 

Lagena foveolata Reuss var. Sidebottom, 1912, Journ. Q. M. 0. r 
p. 395, pi. 16, figs. 16, 17. 

It is possible that further investigation may reveal this to be 
an apiculate form of one of the variations of L. melo d'Orbigny 
sp. Locality .- Nos. 1, 2, 4, 6, 8, 10, 12, 14, 15, 17, 19, 21, 22, 
24, 33, 36, 38, 40, 42-44. 

Lagena foveolata Reuss var. spinipes Sidebottom. 

Lagena foveolata R,3uss var. spinipes Sidebottom, 1912, Journ. 
Q. M. 67., p. 396, pi. 16, figs. 18-20. 

The tests are not in the best condition, and in some instances 
the spines appear to be absent, or scarcely perceptible. The 
rotund form does not occur. Locality : Fifteen specimens at 
at No. 2, three at No. 3, four at No. 4. 

Lagena foveolata Reuss (?) var paradoxa Sidebottom (PI. 15, 

fig. 32). 

Lagena foveolata Reuss (?) var. paradoxa Sidebottom, 1912, 
Journ. Q. M. C, p. 395, pi. 16, figs. 22, 23. 

This is one of the commonest foraminifera in these gatherings. 
The tests vary greatly in size and shape. Locality : Nos. 1-22, 
(except No. 17), 23-26, 29, 31, 33, 34-36, 39-41, 44. 

Lagena lamellata Sidebottom. 

r 

Lagena lamellata Sidebottom, 1912, Journ. Q. M. C, p. 396, 
pi. 16, figs. 24, 25. 

I can only identify four tests. Locality : Two occur at No. 43 i 
the other station or stations are uncertain. 



178 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 

Lagena Hertwigiana Brady (PI. 15, fig. 33). 

Lagena Hertwigiana Brady, 1881, Quart. Journ. Micr. Sci., vol. 21, 

N.S., p. 62. 
Lagena Hertwigiana Brady, 1884, p. 470, pi. 58, fig. 36. 

The figure in my copy of the Challenger Report, pi. 58, 
fig. 36, does not show the reticulation referred to in the description 
of the species in the text, p. 470. In the three or four specimens 
found in these soundings, the surface is roughened and the 
perforations show very plainly. Locality : Uncertain, with the 
exception of No. 43. 

Lagena Hertwigiana Brady var. undulata Sidebottom. 

Lagena Hertwigiana Brady var. undulata Sidebottom, 1912, 
Journ. Q. M. C, p. 397, pi. 16, figs. 26-28. 

Many examples occur. Locality : Nearly all the stations, but 
chiefly Nos. 2, 7, 10, 17, 24, 34, 43. 

Lagena pacifica Sidebottom. 

Xagena pacijica Sidebottom, 1912, Journ. Q. M. C, p. 398, pi. 16 f 
fig. 29. 

Only two or three specimens found. Locality : Uncertain. 

Lagena splendida sp. nov. (PI. 16, fig?. 1-3). 

I am quite at a loss how to describe this exquisite Lagena. 
-adequately, and I am unable to draw it owing to the complexity 
of its decoration, which is exceedingly minute. The test glistens 
and most probably it has been apiculate. The neck is fractured. 
There is a second specimen which I think is the same, but there 
is a slight difference in its appearance which I am unable to 
explain. It is apiculate. Locality : Uncertain. 

Note. Not being able to get a satisfactory definition with my 
microscope, I submitted the test to Mr. Earland for examination, 
who had better means of lighting up the test than I had. His 
observations were made with the assistance of a Zeiss vertical 
illuminator and daylight instead of artificial light. He writes as 
follows : 



HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 179 

" The markings appear to be knife-edged costae, from one side 
of which triangular processes project at intervals. The apex of 
the process barely touches the inner side of the adjoining co^ta. 
. . . The triangular processes are Hush with the costae at their 
base, but apparently sink away towards the apex, which is 
probably but little raised above the wall of the test. The sunken 
parts between the processes have a matt surface, whereas the 
processes and costae are quite translucent." 

I may say that my own examination of the test agrees to a 
great extent with the above, but I think the edges of the costae 
are waved (see PI. 16, fig. 3). 

In a second communication Mr. Earland writes : " I succeeded 
in getting a stereoscopic view of the shell under a ^ in. yesterday, 
and it gave rather a fresh view of its structure. It seemed to be 
covered with lines of pyramidal points in broken lines. Each 
pyramid is a blunt spine." 

I have not succeeded, however, in seeing these characters of the 
test. 

The figure (PI. 16, fig. 2) gives the effect of what I think I see 
under the microscope, and it coincides to a great extent with 
Mr. Earland's first description, though the details given in his 
second communication do not appear to me to be necessarily 
contradictory. I wish to acknowledge my sense of the trouble 
Mr. Earland has taken in the matter. 

Lagena spumosa Millett (PI. 16, fig. 4). 

Lagena spumosa Millett, 1901, p. 9, pi. 1, fig. 9. 

Most of the tests are slightly curved at the oral end, but the 
" bird's-clawlike " process is more slender than is indicated in 
Mr. Millett's illustration. Several are more elongate than the 
one figured. Locality . Frequent at No. 22 ; Nos. 24. 38, 40, 42, 
43, and a few other stations. 

Lagena spumosa Millett, var. 

Lagena spumosa Millett var. Sidebottom, 1912, Journ. Q. 21. C, 
p. 398, pi. 16, fig. 30. 

It is curious that the aboral end of the test appears to have 
teen slightly abraded, I think in all cases. Locality : Nos. 4, 6, 
7, 10, 11^ 13, 24, 25, 33, 35, 39, 40, 42, 43. 



180 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 

Lagena Chasteri Millett. 
Lagena Chasteri Millett, 1901, p. 11, pi. 1, fig. 11. 
See my remarks on the type-form + p. 398. 

Lagena Chasteri Millett (var. ?). 

Lagena Chasteri Millett (var. ?) Sidebottom. 1912, Journ.. 
Q.M.C., p. 398, pi. 1G, figs. 32-34. 

Many occur, but I am quite unable to separate this variation 
from the type, for the curious little " stopper " at the orifice is 
never so pronounced as in Mr. Millett's figure, and is often 
apparently absent. Taking the type-form and the variation to- 
gether, for they are mixed on the slides, they occur as follows : 
Locality ; Nos. 1-4, 22, 34, 38, and frequently at Nos. 42-44. 

Lagena pannosa Millett var. 

Lagena pannosa Mille;t var. 1901, p. 11, pi. 1, fig. 14. 

It is probable that two or three examples of this variation are^ 
present. Locality : Uncertain. 

Lagena intermedia Sidebottom. 

Lagena intermedia Sidebottom, 1912, Journ. Q.M.C., p. 399,. 
pi. 17, figs. 1-3. 

Locality : Nos. 3, 11, 12, 23, 24, 29, 32, 39-41. 

Lagena quadralata Brady. 

Lagena quadralata Brady, 1881, Qua/rt. Journ. Micr. Sci., vol. xxL 

(N.S.), p. 62. 
Lagena quadralata Brady, 1884, p. 464, pi. 61, fig. 3. 

In the Challenger Report Brady states that this Lagena is. 
allied to the Lagena alifera of Reuss. I should prefer to con- 
sider it as a variety of L. lagenoides Williamson var. tenuistriata 
Bradv, for we know that this latter occurs in the trifacial 
condition (see * PI. 19, fig. 5), and therefore it is not surprising 
to find it with four equidistant keels ; also I have a good example 
of Jj. lagenoides with five equidistant keels. The specimen found 
is very small and not in the best condition. I think the wings 
are tubular, but cannot be certain. On the same slide there- 



HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 181 

are two examples with three keels, and two with five keels. 
Locality : One specimen at No. 1. Other stations uncertain. 

Note. One or two examples occur with four keels which are 
not tubulated. These I should place as a variety of L. striata. 

Lagena sp. in cert. 

Lagena sp. incert. Sidebottom, 1912, Journ. Q. M. C, p. 399, pi. 17, 
figs. 4, 5. 

Locality : Three examples at No. 2, two at No. 24. 

Lagena laevigata Reuss, sp. (PL 16, fig. 5). 
Fissurina laevigata Reuss, 1850, p. 366, pi. 46, fig. 1. 

Large and small examples of the type-form occur, but they are 
not numerous. It is impossible to separate L. laevigata from 
L. acuta, as the one passes insensibly into the other. Many other 
examples are present in which the orifice is not central. Forms 
ranging round Fissurina oblonga Reuss, 1862 (1863), pi. 7, fig. 89, 
are frequent, and are found at many stations. A few specimens 
occur that are circular in outline. 

PI. 16, fig. 5. There are two sets of these and they vary a little. 
Some have the appearance of being subcarinate, but this seems 
to be caused by the test being clearer at its edge than at any other 
part. Only two or three examples have the spines at the orifice 
well developed, and most have a small wing at either side of the 
neck. There is no internal tube. Locality : Nos. 42-44. 

Note. These are not far removed from L. falcata Chaster, 
1892, p. 6, pi. 1, fig. 7. On another square (locality uncertain) 
there is one typical form, and there are also one or two others 
that are carinate at the base, which seem to be intermediate 
between L. falcata and Mr. Millett's figure of L. marginata var. 
Millett, 1901, p. 497, pi. 8, fig. 21. 

Lagena laevigata Reuss sp. var. virgulata Sidebottom (PI. 16, 

fig. 6). 

Lagena laevigata Reuss sp. var. virgulata Sidebottom, 1912, 
Journ. Q. 21. C, p. 400, pi. 17, fig. 8. 

PI. 16, fig. 6. A few fine examples placed amongst others which 
are too opaque for me to be certain whether they belong to this 
variation. Locality : Uncertain. 



182 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC^ 

Lagena laevigata Reuss sp. var. 

Lagena laevigata Reuss sp. var. Sidebottom, 1912, Journ. Q. M. 0. T 
p. 400, pi. 17, fig. 7. 

+ P1. 17, fig. 7. Very rare. Locality : Nos. 15, 34. 

Lagena acuta Reuss sp. (PI. 16, fig. 7). 

Fissurina acuta Reuss, 1862, p. 340, pi. 7, fig. 90, and F. apiculata r 
p. 339, pi. 6, fig. 85. 

Lagena acuta (including such as have only the slightest indica- 
tion of the apiculate process) is found at almost all the localities.. 
The size and inflation of the tests, as well as their outlines, vary 
greatly. Two at No. 14. 

Lagena acuta Reuss sp. var. (PI. 16, fig. 8). 

The chief feature of this variety is the curious oval marking at- 
the base, on both sides of the test. It is very rarely so clearly- 
shown as in the drawing. The tests are opaque or nearly so, and 
when the shell-substance becomes very dense the markings 
disappear, but if damped some trace of them can be detected. 
Locality : Nos. 3-7, 9-11, 13 15, 29, 33, 34, 39, 40, 42, 44. 

+ P1. 17, fig. 9. The mixing of this form w T ith that of fig. 10' 
prevents me from giving the exact localities, but it is evidently 
rather rare. They correspond with the Fissurina apiculata Reuss,. 
1862, p. 339, pi. 6, fig. 85. 

Lagena acuta Reuss sp. var. virgulata Sidebottom. 

Lagena acuta Reuss sp. var. virgulata Sidebottom, 1912, Journ.. 
Q.M. C, p. 401, pi. 17, fig. 10. 

+ P1. 17, tig. 10. This appears to occur at nearly all the 
stations up to No. 22, after which it is extremely rare. 

Lagena acuta Reuss sp. var. 

Lagena acuta Reuss sp. var. Sidebottom, 1912, Journ. Q. M. C^ 
p. 401, pi. 17, fig. 11. 

Locality : Nos. 3, 4, 6, 10, 11, 14, 24, 25, 34, 39. 



HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 183 

Lagena lucida Williamson sp. (PI. 16, rig. 9). 

K iitosolenia marginata var. lucida Williamson, 1848, p. 17, pi. 2, 
fig. 17. 

There are nine examples which are nearly circular in outline., 
and subcarinate. Locality : No. 44. 

PL 16, fig. 9. I believe this to be an elongate form of L. lucida, 
in which the characteristic markings are only feebly represented. 
The shell is very little compressed. Two or three specimens only 
oocur. Locality : Uncertain. 

One or two tests are present which are intermediate between 
the type and the elongate form referred to above. Several are 
apiculate. Locality : Nos. 1, 6, 14, 21, 22, 24, 38, 42, 43. 

Lagena multicosta Karrer sp. 

Fissurina multicosta Karrer, 1877, p. 379, pi. 16 6, fig. 20. 
Fissurina bouei Karrer, p. 378, pi. 16 6, fig. 19. 

The examples are small, and some are without the irregularity 
of the costae characteristic of the type. Locality : Nos. 24, 29, 34, 
35, 39, 42-44, and one or two of the earlier stations. 

Lagena fasciata Egger sp. (PI. 16, figs. 10-13). 
Oolina fasciata Egger, 1857, p. 270, pi. 5, figs. 12-15. 

PI. 16, fig. 10. Beautiful specimens occur which have the mouth 
protruding, and the orifice composed of a line of pores. The 
bands are flush or nearly so. Large and small tests are on the 
slide. Locality: Nos. 1, 3-5, 7, 10, 22, 44, and several other 
stations which are uncertain. 

PI. 16, fig. 11. An apiculate form w r hich is extremely rare. 
The edge of the test is flattened, and has a very fine groove 
running down its centre. The orifice appears to be composed of a 
line of pores. Locality : Uncertain. 

PI. 16, fig. 12. Slightly apiculate, the orifice large, and the 
entosolenian tube divided at the end. The edges of the bands, 
which are not interrupted at the base, appear to be somewhat 
raised. When the test is opaque it is difficult to make out the 
bands. Locality : Nos. 24, 34, 36, 43, 44 : frequent at No. 44. 

PI. 16, fig. 13. The test is apiculate and the opaque bands 
which appear to be flush with the surface are continuous that is,. 



184 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 

not interrupted at the base as is usual in the type-form. About 
thirty specimens on the slide. Locality ; Nos. 42-44. 

Lagena fasciata Egger sp. var. spinosa Sidebottom. 

Lagena fasciata Egger sp. var. spinosa Sidebottom, 1912, Journ. 
Q. M. C, p. 402, pi. 17, figs. 16, 17. 

"*"P1. 17, fig. 16. One or two small specimens. Locality: 
Uncertain. 

+ P1. 17, fig 17. A fair number are present, but they are 
mixed with L. staphyllearia, so I cannot give the localities. See 
remarks * p. 402. 

Lagena fasciata Egger sp. var. carinata Sidebottom (PI. 16, 

figs. 14-16). 

Lagena fasciata Egger sp. var. carinata Sidebottom, 1906, Mem. 

Pro. Lit. Phil. Soc, Manchester, No. 5, p. 7, pi. 1, fig. 17. 
Lagena fasciata Egger sp. var. carinata Sidebottom, 1912, Journ. 

Q. M. 6\, p. 403, pi. 17, fig. 18. 

Pi. 16, fig. 14. The test is compressed, and the keel becomes 
more pronounced as it approaches the base of the shell. The 
internal tube is attached to the back of the test. A few of the 
examples are very fine, like the one chosen for illustration. The 
curved bands seem to be nothing more than an innumerable 
number of pores showing distinctly. In some of the smaller 
examples these bands can hardly be distinguished. It is open to 
question if these forms and the following (PI. 16, fig. 15) would not 
be better placed under L. marginata. Locality : Nos. 1-3, 5-7, 
10, 11, 13 22. 

PI. 16, fig. 15. Test compressed, carinate. The entosolenian 
tube is long and curled at its end. The bands are faintly marked 
as in the preceding form. Locality : Nos. 2-5 ; common at No. 2. 

PI. 16, fig. 16. A solitary example. The edges of the curved 
bands are very slightly raised, and the shell becomes more com- 
pressed as the orifice is approached. The keel is represented by a 
fine ridge only. The specimen is not in a very good condition, 
opaque patches interfering with the definition of the bands, 
especially at their bases. Locality : No. 42. 

+ PI. 17, fig. 18. Two or three examples found. The carina is 
not pointed at the base as in the figure referred to. Locality : 
Uncertain. 



HENRY S1DEB0TT0M ON LAGENAE OF THE SOUTH-WEST PACIFIC. 185 

Lagena staphyllearia Schwager sp. 
Fissurirta staphyllearia Schwager, 1866, p. 209, pi. 5, fig. 24. 

The non-carinate form is rare. The number of spines varies. 
The tube is attached to one side, thus causing the orifice to be 
eccentric. In a few instances of the carinate variety, where only- 
two spines are present, it is impossible to separate them from the 
Fissurina bicaudata Seguenza, which is generally placed with L. 
man/biota. Locality Nos. 1-7, 9-12, 15-25, 29, 33, 34, 36, 37, 
39-43. 

The variety with either the ketl or the lower part of the test 
serrated or partially fimbriated is not so frequent, but occurs at 
many localities. The orifice is central and the sides of the test 
are only slightly carinate. Locality : Nos. 5-8, 10, 11, 14, 15, 18, 
19, 21, 22, 24, 33, 34, 40, 43. 

+ P1. 17. fig. 19. Very rave. Locality : Nos. 2, 3, 15, 22. 

+ P1. 17, fig. 21. This peculiar variety is rather rare. The 
tests are semi-opaque. There is a short entosolenian tube. 
Locality : Nos. 5-11, 13, 21, 23, 25, 36, 39, 40. 

+ P1. 17, figs 22, 23. See remarks * p. 403. Locality: Nos. 
4-6, 8, 10, 22, 23, 33, 39. 

Lagena staphyllearia Schwager sp. var. quadricarinata 

Sidebottom. 

Lagena staphyllearia Schwager sp. var. quadricarinata Sidebottom, 
1912, Journ. Q. M. C, p. 404, pi. 21, fig. 16. 

Locality .- Nos. 2, 5-7, 9, 10, 12, 13, 21, 38, 41. 

Lagena unguiculata Brady. 

Lagena unguiculata Brady, 1881. Quart. Journ. Micr. Sci., vol. 21, 

(N.S.), p. 61. 
-Lagena unguiculata Brady, 1884, p. 474, pi. 59, fig. 12. 

See remarks + p. 404. Locality : Nos. 5-10. 

Lagena quadrata Williamson sp. 
-Entosolenia marginata var. quadrata Williamson, 1858, p. 11, pi. 1, 
fig. 27. 
Both the carinate and non-carinate form are present. Locality : 
Nos. 15, 22, 24, 25, 34, 37, 40, 42-44. 

Journ. Q. M. C, Series II. No. 73. 13 



186 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 

There are several' examples which have a short neck and the 
orifice carrying a short spine at either side. Three or four 
specimens are similar to the one figured by Mr. Millett in his 
Malay Report, 1901, p. 496, pi. 8, fig. 18. 

Lagena marginata Walker and Boys sp. (PI. 16, figs. 17-20, 

fig. 18, trifacial form). 

" Serpula {Lagena) marginata" Walker and Boys, 1784, p. 2,. 
pi. 1, fig. 7. 

This species is exceedingly well represented in these gatherings, 
and in one form or another is found at nearly all the stations. 
The shape of the body of the test varies from flattened to globular, 
and in outline from circular to elongate-pyriform, the carination 
from a fine ridge to a very broad wing. The situation and form 
of the orifice are variable. Apiculate examples are present and 
some have the keel acuminate at the base. 

PI. 16, fig. 17. This agrees fairly well in outline with Fissurina 
paradoxa Seguenza, 1862, pi. 2, fig. 7. The Fissurina bicaudata 
Seguenza, 1862, pi. 2, fig. 16, is also represented, and it is difficult 
in some cases to separate this from L. staphyllearia. 

PI. 16, fig. 18. A trifacial form. If anything, the three faces 
of the body are somewhat concave ; one would rather expect them 
to be convex, judging from trifacial examples that occur in other 
species. The specimens vary very little. Locality ; Nos. 2-4, 
8-10, 14, 15, 22, 29, 34, 36, 39, 40. 

PI. 16, fig. 19. The edge of the test is flattened, the orifice 
fissurine. In some positions it has the appearance of being 
slightly bicarinate, but I do not think it is so. Locality : Nos. 
42, 43. 

PI. 16, fig. 20. This minute variety has a comparatively large 
orifice, which is much compressed and opens out on one side of 
the median line ; the tube is attached to the back of the test, 
which is very slightly carinate. The test is moderately com- 
pressed and curiously tucked in at its base. The specimens are 
mixed with others very similar to them, but which have the 
orifice central and the tube short and straight. There are other 
forms on the same square, so I cannot give the exact localities. 
The two forms mentioned are rare. Both were found at a station 
later in the series than ISTo. 22. 



HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 187 

Lagena compresso-marginata Fornasini (PI. 16, fig. 21). 

Lagena compresso-marginata Fornasini, 1889, Minute Forme di 
Riz. Retic. nella Mama Plioc. del Ponticello di Savena, 
Bologna, fig. 16. 

PI. 16, fig. 21. This is rather a stoutly-built form. The aperture 
is fissurine and the test apiculate. Locality : Nos. 22, 24. 
Rather rare. 

There are a few very small examples that appear to be almost 
identical with Fornasini's figure. Locality : Uncertain. 

+ PI. 17, fig. 30. Only two or three found. Locality: Nos. 
42, 44, and two or three examples at one or two other stations. 

+ PI. 17, fig. 31. Very rave. Locality ; Nos. 2, 4. 

*** PI. 18, fig. 1. Very rare. See remarks + p. 406. Locality ; 
Nos. 2, 5, 7, 19, 24. 

Lagena marginata Walker and Boys var. 

Lagena marginata Walker and Boys var. Sidebottom, 1912, 
Journ. Q. M. C, p. 407, pi. 18, figs. 4, 5. 
Locality: Nos. 4-6, 10-13, 16, 17, 19-23, 25, 36, 40. 

Lagena marginata Walker and Boys var. catenulosa Chapman 

(PL 16, fig. 22). 

Lagena marginata var. catenulosa Chapman, 1895, p. 28, pi. 1, fig. 5. 

Lagena marginata Walker and Boys var. catenulosa (Chapman) 

Sidebottom, 1912, Journ. Q. M. C, p. 407, pi. 18, fig. 6. 

PI. 16, fig. 22. Four examples occur. The one chosen for 
illustration hardly shows a trace of the chain-pattern, and the 
test is free from exogenous shell-growth. The others show the 
chain-pattern. One of the specimens has the body of the test 
covered with exogenous beads. The few tubuli shown in the 
drawing are caused, I believe, by the borings of some animal. 
Locality : Nos. 1, 5, 10. 

Lagena marginata Walker and Boys var. raricostata 

Sidebottom. 

Lagena marginata Walker and Boys var. raricostata Sidebottom, 
1912, Journ. Q. M. C, p. 408, pi. 18, figs. 8, 9. 

*' r PI. 18, fig. 8. Over twenty specimens are on the slide. 
Locality : Nos. 1-3. 



18S HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 

Lagena marginata Walker and Boys var. striolata Sidebottom. 

Lagena marginata Walker and Boys var. striolata Sidebottom, 
1912, Journ. Q. M. C, p. 408, pi. 18, figs. 10, 11. 

+ P1. 18, fig. 10. Locality: Nos. 1, 3, 4, 15, 18-20, 22-25, 34, 
35, 38, 42-44 ; frequent at Nos. 42, 43. 

+ PI. 18, fig. 11. Locality : Nos. 23, 24, 42. 

Lagena marginata Walker and Boys var. elegans Sidebottom. 

Lagena marginata Walker and Boys var. elegans Sidebottom, 
1912, Journ. Q. M. C, p. 409, pi. 18, fig. 12. 

Locality : Nos. 14, 19, 20 ; frequent at No. 14. 

Lagena marginata Walker and Boys var. retrocostata 

Sidebottom. 

Lagena marginata Walker and Boys var. retrocostata Sidebottom, 
1912, Journ. Q. M. C, p. 409, pi. 18, fig. 13. 

Locality : One specimen at No. 2, and one other, station un- 
certain. 

Lagena marginata Walker and Boys var. semimarginata 

Reuss. 

Lagena No. 64, von. Schlicht, 1870, p. 11, pi. 4, figs. 4-6; and 

Xo. 65, p. 11, pi. 4, figs. 10-12. 
Lagena marginata var. semimarginata Reuss, 1870, p. 468. 

An altogether unsatisfactory variation. It occurs in several 
forms at a few stations ; that figured in the Challenger Report, 
pi. 59, fig. 19, occurs at No. 44. 

Lagena marginata Walker and Boys var. seminiformis 

Sch wager. 

Miliola stiligera Ehrenberg (?) 1854, pi. 31, fig. 6. 
Lagena seminiformis Schwager, 1866, p. 208, pi. 5, fig. 21. 

Four large examples occur, similar to those figured in the 
Challenger Report, pi. 59, figs. 28-30. Locality; Nos. 5, 16, 17. 






HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 189 

"*" PI. 18, fig. 16. Extremely rare, only one or two being found. 
Locality ; Uncertain. 

"i" PI. 18, fig. 17. Locality-. Nos. 1-3, 15. Three examples at 
two or perhaps three of the four stations indicated ; also six at a 
few other uncertain localities. 

+ PI. 18, fig. 18. Locality: Nos. 1, 3, 13, and several others. 
Very rare. 

** PI. 18, fig. 19. Several have the central spine at the base of 
the same length as the other two. Locality : Nos. 2, 3, 6-8, 10, 
11, 24, 34-36. 

Lagena marginato-psrforata Seguenza (PI. 16, figs. 23-25). 
Lagena marglaato-perforata Seguenza, 1880, p. 332, pi. 17, fig. 34. 

Very numerous. The variety with no keel is rare. The shape 
of the test varies a good deal as regards compression and length. 
In a few cases, fine lines, running the length of the test, make 
their appearance. At the edge of the test, the markings are 
sometimes arranged in a line. Locality : Nos. 1, 2, 4, 5, 7-15, 19, 
20, 22-25, 29, 38-40, 42-44. 

PI. 16, fig. 23. This is nearly circular in section near the base, 
and becomes compressed as the orifice is approached. Tube 
straight. Ptare. Locality : No. 14. 

PI. 16, fig. 24. In this example fine pores are seen, but with 
few exceptions the centre of each face of the test is free from 
them. One specimen is in the trifacial condition. Locality ; 
Nos. 23-25, 29, 33, 36, 38, 39. 

PI. 16, fig. 25. Test well compressed, subcarinate. Except for 
the two lines of pores that run round the test close to its edge, 
the faces are almost free from them. The shell is partially 
clouded. Fairly frequent. Locality : Uncertain. 

Lagena Wrightiana, Brady. 

Lagena Wrightiana Brady, Quart. Journ. Micr. ScL, vol. 21,1881, 

p. 62. 
Lagena Wrightiana Brady, 1884, p. 482, pi. 61, figs. 6, 7. 

The central part of the faces of the test is not always smooth. 
Very rare. Locality : Nos. 37, 42, 43. 



190 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 

Lagena lagenoides Williamson sp. (PI. 16, figs. 26-29, and 

pi. 17, fig. 1). 

Entosolenia marginata Walker and Boys var. lagenoides 
Williamson, 1858, p. 11, pi. 1, figs. 25, 26. 

This and its numerous variations are well represented. PI. 16, 
figs. 26, 27. I was tempted to place these under L. marginata, 
but the appearance of the wing caused me to hesitate and to 
submit a specimen to Mr. Earland for examination. He reported 
that the wing was tubulated, being " infiltrated with amorphous 
carbonate of lime subsequent to the death of the animal." Mr. 
Millett considers that if tubuli are present " their affinity would 
be with L. lagenoides rather than with L. marginata." Besides 
the two forms figured, both large and small circular examples 
occur in the same condition, only with the tubuli showing more 
plainly. 

PI. 16, fig. 28 represents one of the small examples. There are 
also specimens which are apparently of exactly the same form, in 
which the tubuli, if present, must be extremely minute. It would 
appear therefore necessary to submit all such forms to critical 
examination. Locality : Nos. 5-7, 11, 14, 15, 18-22. 

PI. 16, fig. 29. In this instance the keel is twisted at the base. 
Four specimens found. Locality : Uncertain, but after station 
No. 22. 

PI. 17, fig. 1. The test is well compressed and the orifice also. 
Entosolenian tube short and curled. Locality : Ncs. 42-44 ; 
frequent at Nos. 43, 44. 

+ P1. 18, fig. 22. The form occurring is very similar to the 
figure referred to. It is rather smaller and the keel is narrower 
and thicker ; the neck and phialine orifice are the same. Locality ; 
Nos. 1-3, 42-44. 

Six large specimens similar to the Challenger Report figure, 
pi. 60, fig. 14, are also present. Very rare. Locality : Nos. 2, 
22, 24. 

Another set is similar to +pl. 19, fig. 4, but the tests are not 
striated. Frequent. Locality : Nos. 2-8, 11. 

+ PI. 18, fig. 23. See remarks, +p. 412. Locality : Nos. 2, 36, 
38, 39. 

+ P1. 18, fig. 29. Typical examples are very rare and not so 



HENRY SIDEBOTTOM OX LAGENAE OF THE SOUTH-WEST PACIFIC. 191 

large as the specimen referred to. Locality : No. 3, and either 
No. 35 or 39. 

Besides the above, there are a few specimens which are much 
smaller, especially in the width of the test. Locality : Nos. 17, 
19, and one or two other stations. 

Lagena lagenoid.es Williamson sp. var. nov. duplicata 

(PI. 17, fig. 2). 

The test is bicarinate ; aperture oval and the keels tubulated. 
Six specimens found. Locality : Nos. 24, 37. 

Lagena lagenoides Williamson sp. var. tenuistriata Brady. 

Lagena tubulifera var. tenuistriata Brady, 1881, Quart. Joiirn. 

Micr. Sci. vol, 21 (N.S.), p. 61. 
Lagena lagenoides Williamson var. tenuistrata Brady, 1884, p. 479, 

pi. 60, figs. 11, 15, 16. 

*P1. 19, fig. 4. Very frequent. These correspond to the 
Challenger Report, pi. 60, fig. 11. The trifacial form also occurs. 
Locality ; Nos. 1-11, 13, 14, 17, 21-24, 29, 31, 33-35, 37, 39-41. 

There is another set of specimens which are not quite so large 
and have the costae on the body of the test, farther apart. 
Locality : Nos. 14, 15, 17, 18. 

There are a few large specimens very similar to the Challenger 
Report, pi. 60, fig. 15. In the stouter examples the fine costae 
coalesce to such an extent that the surface has a pitted appear- 
ance. Locality: Nos. 2, 8, 11, and one or two other stations. 

Lagena formosa Schwager (PI. 17, figs. 3-7). 

Lagena formosa (pars) Schwager, 1866, p. 206, pi. 4, fig. 19. 
Lagena formosa (Schwager) Brady, 1884, p. 480, pi. 60, figs. 10, 
18-20. 

This is present in many forms ; some show the raised border 
punctate, others do not. See remarks **" p. 414. 

PI. 17, fig. 3. In this, which is obviously of the same kind as 
fig. 18, pl. 60, in the Challenger Report, the raised border is 
absent. Others agree with this figure, also with the Challenger 
Report, fig. 20. 

Several very fine specimens are intermediate between fig. 18 
and L. formosa var. favosa Brady, on the same plate, fig. 21. 



192 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACTFIC 

They are heavily punctate at the base of the neck, and costae just 
start to run clown the keels. Many small examples occur, which 
come under this unsatisfactory species, but as they are mixed on 
the various squares I can only give the stations for the whole 
series. Locality : Nos. 1-8, 10, 11, 13, 14, 17, 21, 23-25, 29, 
37, 39-41, 43. 

PI. 17, fig. 4. The keel splits near the top, and the space thus 
formed is filled with shell-growth. The specimens are not in a 
satisfactory condition for examination, so I cannot say if the 
tubuli in the keel occupy the whole of the space. The punctate 
border does not seem to be raised, and it shows clearer in substance 
than the rest of the test. I believe this is the same as Challenger 
Report, pi. 60, fig. 10. Locality : No. 44. 

PI. 17, fig. 5. T am inclined to believe that the keel has broken 
away in these specimens, of which there are seven. They are all 
in the same condition ; the drawing shows how the keel has 
begun to split. Locality . Nos. 43, 44. 

+ PI. 18, fig. 24. I am now inclined to believe that in this 
case also the keel has become fractured. 

PI. 17, fig. 6. This has a likeness to the preceding pi. 17, fig. 5. 
The keel, which commences at the neck, soon splits and joins the 
two borders ; the space between them is filled with shell-growth. 
The test has a very compact look and the tubuli show clearly. 
Rare. Locality : Nos. 42, 43. 

PI. 17, fig. 7. A solitary specimen in good condition. The keel, 
commencing at the orifice, dies away about half-way down the 
test. A few well-marked pores are scattered on each face of the 
test. At the base are several short costae. Locality ; No. 37. 

+ P1. 19, fig. 9. See remarks, + p. 414. Frequent. Locality : 
Nos. 1, 2, 10, 11, 14, 17-19, 22. Over twenty examples occur after 
station No. 22, but the exact stations are uncertain. 

Lagena formosa Sch wager, var. (PI. 17, fig. 8). 

The drawing of this variety must be taken more or less as 
diagrammatic. The test, which has three keels (the central one 
commencing at the aperture) is in an opaque condition. The 
spaces between the keels are filled with shell-growth. The tubuli 
hardly show, unless the shell be moistened. The body of the test 
has fine costae running lengthwise, and is finely pitted. There* 



HENRY SIDEBOTTOM ON LAGEXAE OF THE SOUTH-WEST PACIFIC. 193 

are only two specimens and they are exactly alike. Locality .- 
No. 40. 

Lagena formosa Schwager var. comata Brady. 
Lagena formosa var. comata Brady, 1884, p. 480, pi. 60, tig. 22. 

A few large specimens occur very similar to the Challenger 
examples, pi. 60, tig. 22. Locality : Nos. 5, 6, 33, 34. 

+ P1. 19, fig. 11. A single example. Locality: Uncertain. 

+ P1. 19, fig. 12. Very rare. Locality : Nos. 6, 10, 22, and 
one or two stations which are uncertain. 

Lagena squamoso-alata Brady (PI. 18, fig. 20). 

Lagena squamoso-alata Brady, 1881, Quart. Journ. Jlicr. Sci. 

vol. 21 (N.S.), p. 61. 
Lagena squamoso-alata Brady, 1884, p. 481, pi. 60, fig. 23. 

A single example occurs, which is typical, except that the 
produced neck is absent, having most probably been broken off. 
Locality : No. 23. 

PI. 18, fig. 20. Besides the above typical specimen, there are 
twenty-two tests which are smaller and not so robust. They 
answer to Brady's description of the species. The pittings on the 
body of the test have a tendency at times to arrange themselves 
in lines. The raised border appears to be punctate. It is 
difficult to make out the markings on the wings, owing to debris, 
but they can be detected in some of the specimens. I believe the 
wings to be cellulated. Brady, in the Challenger Report, only 
mentions that they have radiate markings ; but on examining the 
edges of my typical specimen it is apparent that the wings are 
cellulated. I take this form to be simply a variety of L. formosa. 
One example is in the trifacial condition. Locality ; Nos. 24, 25, 
34, 36. 

Lagena quadrangularis Brady. 

Lagena quadrangularis Brady, 1884, p. 483, pi. 114, fig. 11. 
Lagena quadrangularis (Brady) Millett, 1901, p. 625, pi. 14, 
% IT. 

A single typical specimen, but the neck appears to be fractured. 
Locality ; Either No. 14 or No. 22. 



194 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 

Lagena Orbignyana Seguenza sp. (PI. 17, figs. 9-11). 

Entosolenia mdrginata (pars) Williamson, 1858, p. 10, pi. 1, figs. 

19, 20. 
Fissurina Orbignyana Seguenza, 1862, p. 66, pi. 2, figs. 25, 26. 

This occurs in many forms. Some of the specimens are similar 
to the Challenger Report, pi. 59, figs. 25, 26. Numerous small 
varieties also are present. In some the side keels are little more 
than slightly raised ridges. 

PI. 17, fig. 9. This is a very neat and compact variety. 

The test is moderately compressed. Locality : Nos. 42-44 ; 
frequent at Nos. 42, 44. 

PI. 17, fig. 10. I take this to.be a variety of L. Orbignyana, in 
which the central keel has split soon after leaving the orifice. 
The body of the test is much compressed, and is roughened. The 
entosolenian tube is long and attached. The split keel is entirely 
blocked w T ith debris, or shell-growth. Two examples found. 
Locality : No. 38. 

PI. 17, fig. 11. A neat form. The central keel is emarginate 
at the base, at the middle of which one or two small spines 
project. The two subsidiary keels are not generally continuous. 
There are over one hundred specimens. Locality : Nos. 1, 2, 4-13, 
21, 23, 26, 29, 33, 34, 38, 39. 

Lagena Orbignyana Seguenza sp. var. lacunata Burrows and 

Holland (PI. 17, fig. 12). 

Lagena lacunata (Burrows and Holland) Jones, 1895, p. 205, pi. 7, 
fitf 12 

One set agrees exactly with fig. 1, pi. 60 of the Challenger 
Report, which Messrs. Burrows and Holland point out in the 
above reference, is misnamed as L. castrensis Sch wager. Locality : 
Nos. 42-44 ; frequent at No. 44. 

A few small examples are occasionally met with in which the 
pittings are numerous and minute, and the keels very feebly 
developed. Locality : Uncertain. 

PI. 17, fig. 12. I am treating this as a form of X. Orbignyana 
var. lacunata, but it appears to have one of the characteristics of 
L. annectens (Burrows and Holland) Jones, 1895, for the band 
round the body of the test appears to be very slightly concave. 



HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 195 

The edges of the band are just raised above the surface, and the 
space between is roughened. It will be noticed, by reference to 
the Challenger figure, pi. 60, fig. 1, that there is a ridge, or minor 
keel, between the side keel and the central one, and I take my 
specimens to be in the same condition, only the inner ridge is 
quite close to the central keel. The body of the test is finely 
pitted all over. The aperture is large, compressed and lipped. 
In two cases the keel is serrated all round, but it is doubtful if 
this is natural. The tube is attached. Frequent. Locality : 
Nos. 42, 43. 

Lagena Orbignyana Seguenza sp. var. Walleriana Wright. 

Lagena Orbignyana sp. var. Walleriana Wright, 1886, Proc. JR. Irish 
Acad., ser. 2, vol. iv., p. 611, and 1891, p. 481, p. 20, fig. 8. 

In all the specimens the typical boss is replaced by a ring, 
which is very slightly raised. Locality: Nos. 2, 22, and one or 
more of the three stations, Nos. 42-44. 

Lagena Orbignyana Seguenza sp. var. unicostata Sidebottom. 

Lagena Orbignyana Seguenza sp. var. unicostata Sidebottom, 
1912, Journ. Q. M. C, p. 417, pi. 19, fig. 22. 

The single costa in this case runs the whole length of the body 
of the test. Very rare. Locality ; Nos. 18, 22. 

Lagena Orbignyana Seguenza sp. var. pulchella Brady 

(PI. 17, fig. 13). 

Lagena pulchella Brady, 1866, Rept. Brit. Assoc. (Nottingham), 

p. 70. 
Lagena pulchella Brady, Annals and Mag. Nat. Hist., 1870, p. 294, 

pi. 12, fig. 1. 

The largest specimens are very similar to L. Orbignyana var. 
variabilis Wright, 1891, pi. 20, fig. 9, but the costae are irregular 
and cover the whole of the body of the test ; sometimes there is 
a fine ridge showing between the main keel and the side keels. 
Very rare. Locality : Uncertain. 

A smaller set is frequent, with few and irregular costae. The 
side keels amount to little more than slight ridges. Locality : 
No. 44. 



196 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC* 

A few very small examples are also present. 

PI. 17, fig. 13. This solitary example has the eostae well raised, 
and as they are irregular I have placed it under the above head- 
ing. The side keels are only just apparent. Locality : No. 44. 

+ P1. 19, fig. 24. Very rare. See remarks + p. 418. Locality .- 
Nos. 1, 38. 

Lagena Orbignyana Seguenza sp. var. clathrata Brady 

(PI. 17, fig. 14). 

Lagena clathrata Brady, 1884, p. 485, pi. 60, fig. 4. 

The type-form occurs, but is always rare, except at No. 43, 
where eleven were found. Locality: Nos. 17, 18, 24, 29, 35, 37, 
38, 43, 44. 

A few very small specimens are present, but they are not 
typical. Others are minute, with numerous fine eostae either 
straight or curved, these latter resembling L. variabilis, as Mr. 
Millett remarks in his Malay Report, 1901, p. 628. 

PL 17, fig. 14. I think this may be brought under the above 
heading. The test is compressed and has three keels ; these 
stand out more than the three eostae which run down each face 
of the test. Locality : Nos. 8, 10-14 ; frequent at No. 8. 

Lagena Orbignyana Seguenza sp. var. variabilis Wright. 

Lagena Orbignyana sp. var. variabilis Wright, 1890, p. 482, pi. 
20, fig. 9. 

Except that the side keels are not so well developed, and the 
striae are very numerous, the specimens are fairly typical. In 
several instances the striae are inclined to cover the body of 
the test, and in others they are either absent or scarcely per- 
ceptible. Locality .- 2, 5-7, 10-14, 16-18, 24, 29, 34, 35. 

Lagena Orbignyana Seguenza sp. var. (PI. 17, fig. 15). 

The test is only slightly compressed ; the main keel, which 
starts at the orifice, splits as it approaches the body of the test. 
Very fine bars cross the space thus formed. Between the cross- 
bars is a well-marked circular depression. Besides the side keels 
there are two semicircular eostae, one of these on each face of 
the test. At the base is an irregular circular projection to which 
the keels are attached. The wall of this projection is thin. 



HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 197 



Onlv two specimens were found, each of them badly fractured. 
Both have been utilised in preparing the illustration, which must 
be considered as a drawing of a restored specimen. Locality; 
Uncertain. 

Lagena bicarinata Terquem pp. (PI. 17, figs. 16, 17). 
Fissurina bicarinata Terquem, 1882 7 p. 31, pl. 1 (9), fig. 24. 

The type-form does not appear to be present. 

PI. 17, fig. 16. The tests are in a very opaque condition. 
Locality: Nos. 23, 24, 33, 34, 40. 

PI. 17, fig. 17. There are two or more spines at the base. 
Eleven specimens are in good condition. Locality : Nos. 2-3. 

+ PI. 19, fig. 27. See remarks + p. 419. Locality ; Nos. 2-4. 

A few also occur, very similar to these, except that the body of 
the test is more circular in outline. Locality : Uncertain. 

Lagena bicarinata Terquem sp. var. (PI. 17, fig. 18). 

Test bicarinate. The faces of the test are slightly convex, and 
the two keels slope towards their edges, the effect being that the 
test appears to have a boss on either face. Orifice much com- 
pressed and composed of a row of pores. A solitary specimen. 
Locality : No. 37. 

Lagena bicarinata Terquem sp. var. (PI. 17, fig. 19). 

Test bicarinate and apiculate, with a row of very short tubular 
projections running round the edge of the test between the keels. 
The test becomes more compressed as the orifice is approached. 
Two examples only occur. The neck appears to be broken olT in 
both cases. Locality: No. 43. 

Lagena bicarinata Terquem sp. var. (PI. 17, fig. 20). 

Test bicarinate, the keels generally dying away as they 
approach the orifice, which is composed of a series of fine pores. 
I cannot say if the fine bands, which adorn each face of the test, 
a,re raised or not. Bands of different nature and length are 
found on other species besides L. fasciata, so I prefer to place this 
form under L. bicarinata, instead of treating it as L. fasciata in 
the bicarinate condition. Locality : Nos. 1-10, 13, 15, 16. 



198 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC 

Lagena auriculata Brady (PI. 17, figs. 21, 22, and pi. 18, 

fig. 1). 

Lagena auriculata Brady, 1881, Quart. Journ. Jlicr. Sri., vol. 21 

(N.S.), p. 61. 
Lagena auriculata Brady, 1884, p. 487, pi. 60, figs. 29, 31, 33. 

This is largely represented, especially in its variations ; inter- 
mediate forms occur which it would be interesting to figure. 

PI. 17, fig. 21. In this solitary specimen the wing has divided 
at a point a little above the body of the shell. Locality ; No. 2& 
or No. 39. 

PI. 17, fig. 22. A neat form which appears to be strongly 
built. The shell is moderately compressed. The entosolenian 
tube, when present, is very short and straight. The orifice is 
crowned with a boss, and the loops at the base are feebly 
represented. Nine specimens occur. Locality ; Nos. 2, 10. 

PI. 18, fig. 1. A stoutly-built form. The test is subcarinate,. 
and the orifice situated in a depression. The two loops at the 
base are feebly developed. Very rare. Locality ; Uncertain, but- 
after station No. 23. 

"** PI. 20, fig. 4. A few examples resemble this variation, the 
keel being continuous round the edge of the test. Locality : Nos. 
23, 24, 26, 36, 38, 40, 42, 43. 

"*" PI. 20, fig. 5. There are twelve examples, closely resembling 
this figure, but having no small wings at the top of the test. 
Locality : Nos. 24, 29, 34, 36, 39-41. 

**" PI. 20, figs. 7. 8. A large number are similar to these forms 
and to Challenger Report, pi. 60, fig. 29. Locality : Nos. 2-4,. 
6-12, 17-24, 26 29, 33 35, 38 43. 

+ P1. 20, figs. 9, 10. Some forms present lie more or less 
between the two figures given at this reference. Locality; Nos. 
2-6, 6-11, 17, 18, 21, 22. 

+ P1. 20, figs. 11, 12. Only two or three specimens are near 
+ fig. 11 ; all the rest, and there are over eighty, are like + fig. 12. 
Locality .- Nos. 1-11, 22, 23, 33, 34, 37, 39. Most of them were 
found at Nos. 1-11. 

"*"P1. 20, fig. 13. Nine examples occur, and one is in the 
trifacial condition. Locality ; Nos. 1, 38, 42 44 : the trifacial 
specimen at No. 43. 

*P1. 20, fig. 14. Eight specimens found. Locality; Nos. 1-4. 



HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 199 

Lagena auriculata Brady var. nov. caudata (PI. 18, figs. 2, 3). 

Test compressed, the lower part of the body faintly striated. 
A single long spine, probably always bent more or less to one 
side, projects at the base. Orifice situated at the end of a long 
neck. In fig. 2 the basal spine is partly broken off. 

The faint striation seems to indicate an affinity with L. auricu- 
lata var. costata Brady, but in order to avoid giving subvarietal 
names, I have treated it as a variation of L. auriculata. 
Locality : No. 2. 

Lagena auriculata Brady var. nov. circunicincta (PI. 18, fig. 4). 

Test compressed, subcarinate, except at the lower edge and 
base, where the keel is well developed. A few costae run across 
each face of the test. Orifice oval. Entosolenian tube long and 
curved. Four specimens occur. There are six tests on the 
square, but two do not belong to the same variety. Locality .- 
No. 43, and one of the following stations : Nos. 38, 42, 44, but 
which one is doubtful. 

Lagena auriculata Brady var. nov. clypeata (PI. 18, fig. 5). 

Test compressed, carinate. Orifice oval. Two raised oval 
rings (sometimes slightly irregular) on each face of the shell. 
The loops at the base small. Entosolenian tube long and curved. 
It is easy to miss noticing the loops. The tests vary a little 
from one another in outline. The keel is not quite so wide as 
indicated in the drawing. 

About twenty specimens are arranged on the same square as a 
number of L. Orbignyana sp. var. Waller iana Wright, for which 
they may have been temporarily mistaken. Locality : The 
majority must have been found either at Nos. 42 or 43, or both. 

Lagena auriculata Brady var. Sidebottom (PI. 18, fig. 6). 

Lagena auriculata Brady var. Sidebottom, 1912, Journ. Q. M. C. r 
p. 421, pi. 20, figs. 15-18. 

Pi. 18, fig. 6 and * pi. 20, fig. 15. I have figured one of 
average size. There are often a few spines at the base. 
Locality ; Nos. 4, 23, 24, 38-44. 

A few elongate examples occur. Locality ; Nos. 2. 3- 



.200 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC 

Several approach + pi. 20, fig. 18. Locality : Uncertain. 

+ PI. 20, fiff. 17. A number are near this form, and mixed 
^vvith them are several identical with Mr. Millett's Malay Report, 
pi. 14, fig. 15. Locality : Nos. 1-4. 

A few elongate specimens occur, the body being striated, or 
^wrinkled, as indicated in the figure. Locality : Nos. 8, 9, 11. 

Lagena auriculata Brady var. arcuata Sidebottom. 

Lagena auriculata Brady var. arcuata Sidebottom, 1912, Journ. 
Q. M. C, p. 421, pi. 20, figs. 19, 20. 

+ PI. 20, fig. 19. The specimens differ from the figure, as the 
arches radiate from the base. Locality : Nos. 4-7, 9, 10. 

Lagena auriculata Brady var. costata Brady. 

Lagena auriculata Brady var. costata (Brady) Sidebottom, 1912, 
Journ. Q. M. C, p. 422, pi. 20, figs. 21, 22. 

* Pi. 20, fig. 22. See remarks, + p. 422. Locality : Nos. 23, 
24, 29, 33, 39~ 42. 

Lagena auriculata Brady var. duplicata Sidebottom 

(PI. 18, figs. 7, 8). 

Lagena auriculata Brady var. duplicata Sidebottom, 1912, Journ. 
Q. M. a, p. 422, pi. 20, fig. 23. 

Pi. 18, fig. 7. The loops in this case extend from the base 
almost to the neck. At the first glance, I took the specimens to 
be L. Orbignyana, as in some of the specimens debris or shell- 
growth partially covered the loops, the inner sides of which are 
quite close to the keel ; a closer examination of other examples, 
which are free from debris, show the loops to be complete. 
The tests, of which there are tan, are large. Locality : No. 42. 

Note. The above might, with equal propriety, be treated as 
a carinate form of L. alveolata var. separans Sidebottom, 1912, 
+pl. 21, fig. 4. 

PL 18, fig. 8. This differs from + PI. 20, fig. 23, chiefly in the 



HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 201 

absence of the carina. Very rare. Locality : Nos. 29. 34, 39. 
Two or three were found at other stations besides those indicated. 

Note. Several examples occur almost identical with the above ; 
the only difference being that the loops merge together as in 
L. alveolata, and so must be treated as such. 

* PI. 20, fig. 23. One specimen. Locality: Uncertain. 

Lagena fimbriata Brady (PL 18, tig. 9). 

Lag ena fimbr lata Brady, Quart. Journ. Micr. Sci., vol. 21 (N.S.), 

1881, p. 61. 
Lagena fimbriata Brady. 1884, p. 486, pi. 60, figs. 26-28. 

Two specimens occur similar to the Challenger Report, pi. 60, 
fig. 28. Locality : Uncertain. 

Pi. 18, fig. 9. This is a neat, small, compactly built variety, 
and the fimbriated portion does not appear liable to get fractured. 
The tube is curled upon itself. The test is moderately com- 
pressed, and the opening at the base is very narrow. This variety 
must not be confused w T ith pi. 20, fig. 28. Locality : Nos. 31, 43, 
44 ; frequent at No. 44. 

+ PI. 20, fig. 24. Two examples only occur. Locality : 
No. 31. 

+ P1. 20, fig. 25. Eight specimens. Locality : One or more of 
the following stations : Nos. 5, 6, 22. 

+ PI. 20, fig. 26. Four very fine examples occur. Locality : 
Nos. 4, 6, 8, 10. 

Three specimens, with the base more pointed and the opening 
more contracted, are also on the slide. Locality : Nos. 7, 10, 12. 

Lagena fimbriata Brady var. nov. duplicata (PI. 18, fig. 10). 

Test compressed, ovate. There are two narrow loops, side by 
side, across the width of the test at its base. Tube curled on 
itself. I think the walls of the loops are tubulated, but cannot 
be quite certain about it. A solitary specimen. Locality: 
Uncertain. 

There is another test which has the orifice wider, and the tube 
short and straight. The loops are in the same position, but so 
feebly represented that it is doubtful whether it belongs to the 
above variety. 

Journ. Q. M. C, Series II. No. 73. 14 



202 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 

Lagena fimbriata Brady var. occlusa Sidebottom. 

Lagena fimbriata Brady var. occlusa Sidebottom, 1912, Journ.. 
Q. M. C, p. 423, PI. 20, figs. 27, 28. 

+ PI. 20, fig. 27. Common. Most of the specimens have the 
opening at the base more open than in the illustration. See 
remarks, + p. 423. Locality: Nos. 1-4, 6-13, 15, 17, 19, 22, 24, 
25, 29, 31, 33-35, 37-42. 

Lagena alveolata Brady (PI. 18, figs. 11, 12). 
Lagena alveolata Brady, 1884, p. 487, pi. 60, figs. 30, 32. 

PL 18, fig. 11. The tests are large and strongly built. All are 
in the apiculate condition. The dotted line indicates the 
boundary of the chamber, thus showing the thickness of the 
wall. Orifice oval. Twelve examples occur. Locality : Nos. 1, 5. 

PL 18, fig. 12. There are a large number present. The tests 
are fairly well compressed. The chief peculiarity is that, though 
the entosolenian tube is straight, the orifice opens out well below 
the median line. The part above the j orifice is sharpened. The 
loops at the base are small, and their outer edges do not project 
nearly so far as does the central carina. Locality : Nos. 1-15, 
17-20. 

"** PL 21, fig. 1. Unfortunately the specimens are mixed with 
another species, so that the stations at which they were found 
are uncertain. There are a fair number on the slide. 

**" PL 21, fig. 2. Good examples are present. Locality : Nos. 1, 
3-5, 7, 10, 16, 17. 

Lagena alveolata Brady var. carinata Sidebottom. 

Lagena alveolata Brady var. carinata Sidebottom, 1912, Journ. 
Q. M. C, p. 424, pi. 21, fig. 3. 

This form is very rare in this collection. Locality : Nos. 24,. 
39, 40. 

Lagena alveolata Brady var. substriata Brady. 

Lagena alveolata var. substriata Brady, 1844, p. 488, pi. 6, fig. 34. 

A single specimen. It is not quite typical, the neck of the 
test being more produced than in the Challenger figure. 
Locality : No. 39. 






HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 203 

Lagena alveolata Brady var. separans Sidebottom. 

Lagena alveolata Brady var. separans Sidebottom, 1912, Journ. 
Q. M. C, p. 425, pi. 21, fig. 5. 

Locality: Nos. 1-3, 5, 6, 17-20, 23-25, 34, 38. 

Lagena clypeato-marginata Rymer-Jones var. 

Lagena clypeato-mavginata Rymer- Jones var. Sidebottom, 1912, 
Journ. Q. 21. C, p. 425, pi. 21, fig. 6. 

Several examples occur. Locality : Uncertain. 

Lagena magnifica Sidebottom. 

Lagena magnifica Sidebottom, 1912, Journ. Q. M. 6'., p. 425, 
pi. 21, fig. 8. 

A few of the specimens are in the transparent condition. 
Locality : ]S"os. 1-5, 7. 

Lagena Elcockiana Millett. 

Lagena Elcockiana Millett, 1901, p. 621, pi. 14, figs. 5, 6. 
Lagena Elcockiana (Millett) Sidebottom, 1912, Journ. Q. M. C, 
p. 426, pi. 21, fig. 9. 

A single specimen. Locality : Uncertain. 

Lagena galeaformis Sidebottom. 

Lagena galeaformis Sidebottom, 1912, Journ. Q. M. C, p. 426, 
pi. 21, figs. 11, 12. 

+ P1. 21, fig. 12. Only the trifacial form appears to be repre- 
sented in these gatherings. Locality : Nos. 1-3. 

There are a few tests which may, or may not, be the bifacial 
form of this species. I have included them under **"pl. 20, fig. 17, 
on page 421. They are not so stout as this figure represents, 
and the side keels are entire as far as the tubular process. 

Lagena protea Chaster. 

Lagena protect Chaster, 1892, p. 62, pi. 1, fig. 14. 

See remarks, + p. 427 .Locality : Nos. 2, 10, 17, 19, 22, 23, 25, 
38, 39, 43, 44. 



204 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC 

Lagena invaginata sp. nov. (PL 18, fig. 13). 

Test slightly carinate ; oral end protruding and arched ; 
orifice a narrow slit, perhaps barred. The front highly convex ; 
the back flat, with a large concave recess at the base. The 
entosolenian tube long and bent to one side. Twenty-one 
examples occur. Locality : Nos. 38, 41, 42 ; chiefly at No. 42. 

Lagena reniformis sp. nov. (PI. 18, fig. 14). 

The test reminds one of a kidney bean in shape ; the orifice is 
situated on one side of the median line. The entosolenian tube 
is long and attached. A few of the specimens are not nearly so 
wide in relation to the height as the one figured. Locality : 
About sixteen at No. 44. It occurs also at several other 
stations. 

Lagena reniformis sp. nov. var. (PI. 18, fig. 15). 

I am treating this as a variation of the above. I believe the 
orifice is composed of a series of pores, at any rate it is exceed- 
ingly narrow. There are two other tests along with it, in which 
the width is about equal to the height, but I think they belong 
to the same variety. Locality : Uncertain. 

Lagena reniformis sp. nov. var. spinigera (PI. 18, fig. 16). 

The test is compressed, and the two spines, one on either side, 
project upwards. The orifice is slightly sunk, and the tube is 
long and attached, reaching almost round the shell. Two 
specimens only found. Locality : Nos. 29, 44. 

Lagena sp. incerfc. (PI. 18, fig. 17). 

Probably this is only L. marginata in a contorted condition. 
The test is carinate, compressed and twisted. Two occur. 
Locality : Both at No. 15 ; or one at No. 1 and the other at 
No. 15. 

Lagena lagenoides Williamson sp. var. (PI. 18, fig. 18). 

The test is elongate, not much compressed, and bicarinate. 
Aperture fissurine. The keels, which only project slightly, are 
tubulated. 

I take this to be an elongate variety of L. lagenoides, William- 
son sp., pi. 17, fig. 1. Three occur. Locality : No. 40. 



HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 205 

Lagena staphyllearia Sch wager sp. var. (PI. 18, fig. 19). 

Test compressed (lower part angular in outline) with five very 
small protuberances arranged, as shown in the drawing, on the 
edge of the shell. The entosolenian tube starts straight and 
then bends towards the back of the test. Only four occur, and 
they vary a little in outline. Locality : Nos. 3, 11. 

Lagena sp. incert. (PI. 18, fig. 21). 

I have only made an outline drawing of this form, because I 
am not sure what its natural condition may be. The test 
is compressed, and nearly all the examples are covered with 
shell-growth, which has a sugary appearance. The colour is 
a light cream. In those that are partially free from this in- 
crustation, the test appears to be more or less in a hispid 
condition. The carina, starting at the orifice, often ends abruptly, 
as show r n in the illustration, but sometimes it gradually diminishes 
until it is lost about half-way down the test. Two or more 
spines adorn the base. It may be a compressed form of L. hispida. 
Locality : Nos. 23, 29, 39, 40, 41. 

Lagena sp. incert, (PI. 18, fig. 22). 

I am puzzled with this form, not knowing whether to treat it 
as L. marginata in which the keel has split, thus forming two 
long loops, one on either side of the test ; or, as L. auriculata in 
which the loops extend almost to the neck. It will be noticed 
that the loops are quite separate at the base. Three occur. The 
specimens are mixed with those of another form. Locality : One, 
must have been found at No. 43 or No. 44. 

? Lagena sp. (PL 18, figs. 23, 24). 

I believe this to be a foraminifer, but it is very doubtful if it 
be a Lagena. There was a small test, on the same square, which 
had every appearance of being the initial chamber of the same 
species. Unfortunately, in using a high-power lens for examina- 
tion, I accidentally crushed the specimen ; but I bad previously 
made an outline drawing of it, see pi. 18, fig. 24. 

The large test, pi. 18, fig. 23, is not compressed. The orifice is 
a rosette in form, and the upper part of the test is covered with 
a raised irregular mesh. Rows of tubular projections run at 



206 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 

intervals across the test. It being a solitary example I do not 
care to make a section of it, but probably it would reveal a series 
of chambers. As Mr. Thornhill has placed it among the Lagena, 
and it is such an interesting object, I cannot resist the oppor- 
tunity of figuring it. It is opaque, but the single-chambered 
specimen was quite transparent. Locality : No. 42. 

Lagena maculata sp. nov. (PI. 18, fig. 25). 

I was unable, for various reasons, to make out the nature of 
this interesting species, so submitted the test to Mr. Earland, and 
he has kindly sent me the following description of it : 

"The shell appears to consist of two, probably three layers. 
An inner test which is covered with a raised hexagonal outline 
pattern, like network over a ball, and this in turn is covered 
with an extremely thin outer test. This latter may be merely 
chitinous or membranous ; it is sufficiently thin to show diffrac- 
tion spectra. "Where this outer layer is stretched over the raised 
pattern it is depressed in a rounded fashion, as though it had 
been pressed down with the tip of the finger into the hexagonal 
cavity beneath." 

A solitary example. It belongs to the Waterwitch set of 
Lagenae. Test not compressed. 

Locality : No. 13. Station 238, Lat, 12"44' S., Long. 179*09' W. 
(1,050 fms.). 

Lagena marginata Walker and Boys var. ventricosa Silvestri. 

Lagena ventricosa Silvestri, 1903-1904, Accad. Reale delle Scienze 
di Torino, p. 10, figs. 6 a-e. 

This seems to me simply a stout form of L. marginata. There 
are eleven large specimens, but the carina is carried a little 
farther up the test. Three of the tests are nearly round in 
section. Examples moderately compressed, with orifice of the 
same character, I have placed with L. marginata. Locality : 
Nos. 5, 15. 

[Mr. Henry Sidebottom has decided to make a type -slide of the 
species described in his two papers as an index to the collection 
of Lagenae. The collection will then be presented to the British 
Museum (Natural; History), South Kensington, under the title, 
<l The Thornhill Collection of Lagenae (South-West Pacific)." 



HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 207 



DESCRIPTION OF PLATES. 



Figs. 



1-3. 


L. 


4. 


L. 


5,6. 


L. 


7,8. 


L. 


9,10. 


L. 


11. 


L. 


12, 13. 


L. 


1-1. 


L. 


15. 


L. 


16. 


L. 


17. 


L. 


18, 19. 


L. 


20. 


L. 


21. 


L. 


22. 


L. 


23. 


L. 


24, 25. 


L. 


26. 


L. 


27. 


L. 


28. 


L. 


29. 


L. 


30. 


L. 


31. 


L. 


32. 


L. 


Q D 

-DO. 


L. 



Plate 15. 

glohosa Montagu sp., x 50 

apiculata Reuss sp., x 25 

longispina Brady, x 50 

botelliformis Brady, x 50 

laevis Montagu sp., x 50 

aspera Beuss, x 50 

aspera Reuss, x 75 

rudis Reuss, x 50 

hispida Reuss, x 50 . 

hispida Reuss var. tuhulata Sidebottom, x 50 

striata d'Orbigny sp., x 75 . 

costata Williamson sp., x 75 

acuticosta Reuss, x 50 

hexagona Williamson sp., x 50 

hexagona Williamson sp., x 115 

hexagona Williamson, sp., compress 

X 115 

sulcata Walker and Jacob sp., x 50 

ph<migera Brady, x 50 

semilineata Wright, x 50 . 

crenata Parker and Jones, var. x 50 

Thomhitti Sidebottom, x 75 

stettigera Brady var. eccentrica Sidebottom, x 50 

stelligera Brady var. eccentrica Sidebottom, com 

pressed variety, x 50 . 
foveolata Reuss (?), var. paradoxa Sidebottom, x 75 
Hertv:igiana Brady, X 50 . 



ed varietv 



Page 

164 

165 

165 

166 

166 

167 

167 

168 

168 

168 

169 

170 

171 

171 

171 

171 
172 
173 
173 
174 
174 
175 

175 

177 
178 



208 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 



Plate 16. 

Figs. 

1. L. splenclida sp. nov., x 75 

2, 3. Diagrams of decoration ...... 

4. L. spumosa Millett, x 75 . . . 

5. L. laevigata Reuss sp., x 115 

6. L. laevigata Keuss sp. var. virgulata Sidebottom, x 50 

7. L. acuta Reuss sp. x 25 . . . 

8. L. acuta Keuss sp. var., X 50 . 

9. L. lucida Williamson sp., X 50 
10-13. L. fasciata Egger sp., X 50 

14. L. fasciata Egger sp. var. carinata Sidebottom, X 25 

15, 16. L. fasciata Egger sp. var. carinata Sidebottom, x 50 

17. L. marginata Walker and Boys, x 50 

18. L. marginata Walker and Boys, x 75, 

form . . . 

19. 20. L. marginata W T alker and Boys, x 75 

21. L. compresso-marginata Fornasini, x 75 

22. L. marginata Walker and Boys, var. 

Chapman, x 25 . 

23. 24. L. marginato -perforata Seguenza, x 50 
25. L. marginato-perforata Seguenza, x 75 
26-28. L. lagenoides Williamson sp., x 50 . 
29. L. lagenoides Williamson sp., x 75 . 



Trifacial 



catenulosa 



Page 

178 

178 

179 

181 

181 

182 

182' 

183 

183 

184 

184 

186- 

186. 
186 
187 

187 
189 
189 
190 
190 



HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 209' 



Plate 17. 

Figs. 

1. L. lagenoides Williamson sp., x 75 . 

2. L. lagenoides Williamson sp. var. nov. duplicate/,, X 75 

3. L.formosa Schwager, x 50 
4-7. L.formosa Schwager, x 75 

8. L. formosa Schwager var., x 75 

9. L. Orbignyana Seguenza sp., x 75 

10. L. Orbignyana Seguenza sp., x 50 

11. L. Orbignyana Seguenza sp., X 75 

12. L. Orbignyana Seguenza sp. var. lacunata Burrows 

and Holland, x 50 

1 3. L. Orbignyana Seguenza sp. var. pulcheUa Brady, X 75 

14. L. Orbignyana Seguenza sp.var. clathrata, Brady, x 75 

15. L. Orbignyana Seguenza sp. var., x 75 

16. 17. L. bicarinata Terquem sp., x 50 

18. L. bicarinata Terquem sp., x 75 

19. L. bicarinata Terquem sp., x 75 

20. L. bicarinata Terquem sp., x 75 

21. L. auricidata Brady, x 50 

22. L. auricalata Bradv, x 75 



Page 

190 

191 

191 

191 

192 

194 

194 

194 

194 

195 

196 

196- 

197 

197 

197 

197 

198 

19& 



'210 HENRY SIDEBOTTOM ON LAGENAE OF THE SOUTH-WEST PACIFIC. 



Plate 18. 

Figs. 

1. L. auriculata Brady, x 75 

2, 3. L. auriculata Brady var. nov. caudata, x 25 . 

4. L. auriculata Brady var. nov. circumcincta, X 115 

5. L. auriculata Brady var. nov. clvpeata, x 115. 

6. L. auriculata Brady var., x 75 

7. L. auriculata Brady var. duplicata Sidebottom, x 25 

8. L. auriculata Brady var. duplicata Sidebottom, x 50 

9. L. fimbriata Brady, x 75 

10. L. fimbriata Brady var. nov. duplicata, x 75 

11. L. alveolata Brady, x 50. 

12. L. alveolata Brady, x 75 

13. L. invaginata sp. nov., x 115 . 

14. L. reniformis sp. nov., X 75 

15. L. reniformis sp. nov. var., x 75 

16. L. reniformis sp. nov. var. spinigera, X 7 

17. Lagena sp. incert., x 75 . 

18. L. lagenoides Williamson sp. var., x 50 

19. L. staphyllearia Sch wager sp. var., x 75 

20. L. squamoso-alata Brady, x 75 

21. Lagena sp. incert., x 75 . 

22. Lagena sp. incert., x 50 . 

23. 24. (?) Lagena sp., x 50 
2?. L. maculata sp. nov., x 75 



Page 

198 
199 
199 
199 
199 
200 
200 
201 
201 
202 
202 
204 
204 
204 
204 
204 
204 
205 
193 
205 
205 
205 
206 



Journ. Quekett Microscopical Club, Scr. 2, Vol. XII., No. 73, Noc mber 1913. 



Journ.Q.M.C. 



Ser. 2, Vol. XII. PI. IS. 




H.Sidebottoni del.ad nat. 



West, Newman lith. 



Laqenae of the South West Pacific Ocean. 



"d 



Jour n. O.M.C. 



Sep. 2, Vol. XII. PL 16. 






A l 















6a 





V 



C 




H.Side~bottom del.adn.at. 



We s t .Newman 



Lagenae of the South West Pacific Ocean. 



Joum. Q.M.C. 



Ser. 2, Vol. XII, PI. 17. 











. 



8a 



. ?2 



* ;-;:. ^\ 
':-V- X-- 

v 








il&K 9 






10a 




b 



Y 



Mi 



, 



. b 






[ 



B 



- - 





H.StdebottOTn del. ad nat. 



West,Newman lith. 



Lagenae of the South West Pacific Ocesun. 



Journ . Q.M.G. 



Ser.2,Vol.XII,P1.18. 






jeST?**^. 






5a b 
























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10a 



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k 



11 







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13a 




ms 



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H.Sidebotfcom del. ad na: 



We s b, Ne wm ax. 



Lagenae of the South West Pacific Ocean. 



211 



GASTROTRICHA. 

By James Murray, F.R.S.E. 

Communicated by D. J. Scourjield. 
{Bead October 28th, 1913.) 

Plate 19. 

INTRODUCTION. 

I have been reluctant to attempt an introduction to the study 
of the Gastrotricha, since my knowledge of the group is by no 
means profound, and such as it is has been only recently acquired. 
Jt is a group which has now reached such dimensions that it is 
desirable there should be in the English language some sort of 
synopsis of our present knowledge, and as there appears to be no 
one else in the field to supply this want, I shall here do the best 
I can. 

The main part of this paper is an annotated bibliography, 
which I hope will save students much of the trouble I have had. 
It is difficult to hit a just mean between giving too much and tco 
little. If too comprehensive and not annotated, a bibliography 
rather hinders than helps by making the mass of works to be 
consulted seem too great. A work is judged by its title to be one 
that must be consulted, and after much labour is found to be of 
no importance. I had a long search for a new genus and species, 
Gastrochaeta ciliata, described by Grimm, before I found that the 
name occurred in a mere list, in Russian, without a figure, 
and that in a footnote all the comparison made was with species 
of Desmoscolex, which belongs to a quite different group of 
worms (25). 

If the bibliography is too condensed the student is always 
liable to suspect that a work omitted from it has not come to the 
knowledge of the compiler. Such things frequently happen. I 
have here tried to keep a proper balance. All important 



212 J. MURRAY ON GASTROTRICHA. 

general, biological and systematic works known to me are 
included, as well as any really important faunistic studies. 
Every work is given in which new species, or supposed new 
species, or groups of higher value are described. The systematic 
student wants these principally. There are omitted all merely 
popular accounts, all trifling faunistic studies (records usually of 
doubtful value), all references in textbooks of zoology which 
contain nothing fresh, pronouncements on systematic position, 
which are mostly only opinions not backed by personal knowledge 
of the animals. 

Monographists and close students of distribution will require 
more than this bibliography contains, but they will be able to 
get it for themselves. 

It is unfortunate that the Gastrotricha, which include those 
old familiar friends of the students of pond life Chaetonotas 
larus and Ichthydium podura have no popular name. Gosse's 
proposed name of " hairy-backed animalcules " is entirely un- 
suitable, since some of the genera are not hairy-backed 
[Ichthydium, Lepidoderma). I confess I am unable to suggest 
any appropriate name. The name suggested by the scientific 
term for the whole group, which embodies almost the only 
character which they all possess, is unsuitable for popular use_ 
The Gastrotricha are not animals which can be named off- 
hand. The days when we found Chaetonotus larus and 
Ichthydium podura, occasionally varied by C. maximus, on all our 
pond- life excursions are over. There are a host of Chaetonoti 
which have contributed to the records of 0. larus. These species- 
are all alike to a casual glance, but are distinguished by minute 
characters the possession of small branches by certain of the 
bristles, the form of the minute scales which bear the bristles r 
etc. Some of these are so delicate that a high power and an 
oil-immersion lens would be needed for their certain deter- 
mination. This is impossible to apply to a living and lively 
Chaetonotus, and as to killing the creature merely in order to 
find out its name, well a philosophic naturalist might prefer- 
to remain ignorant. To destroy this marvellous little living 
gem simply to know how to label it ; is it worth while 1 

Now we students of microscopic life cannot pretend to be 
squeamish ; we have learned to kill lightly ; every time we clean, 
a cover-glass we annihilate a world. But when it comes to 



J. MURRAY ON GASTROTRICHA. 213 

deliberately ending the individual life which we have before our 
eves, intelligent, and surely innocent, I confess that, old and 
hardened as I am at the game, I feel guilty of murder. 
My ideal is that realised by Mr. Bryce, with his " zoo " of 
Rotifera, all kept alive in cells, visited again and again for weeks 
and months, till they become old familiar friends, each known by 
sight and name : where a death in the family is regretted, and 
the beasties, in fact, reach a ripeness of old age which must be 
rare under natural conditions. 

I wish to thank Mr. Rousselet and Mr. Bryce for the assistance 
they have given me in preparing this paper, by lending me 
specimens and books, and Mr. Harring for bibliographical refer- 
ences and extracts from works which I had not seen. 

Form axd Structure. 

AH Gastrotricha are built on a very uniform plan. Most of 
them have a roundish, often 3- or 5-lobed head, a more or less 
distinct neck and a slightly expanded body, diminishing pos- 
teriorly to a usually forked, but sometimes undivided extremity 
{tail or foot). The principal external features are : the tubular 
mouth, certain sensory hairs on the head, various forms of scales 
and hairs clothing the dorsal surface. The ventral surface is 
traversed for its whole length by two bands of vibratile cilia, by 
which the creatures can creep in the manner of an Adineta, and 
sometimes even, apparently, swim. A few possess clear bodies 
which have been supposed to be eyes. 

Of the internal structure I shall say little, as I have given it 
little study, and I can only quote from authors who have studied 
it. The animals are on about the same plane as the Rotifera for 
complexit}', but they look much simpler fewer organs are readily 
visible. A casual examination shows only a thick skin and the 
body cavity, through which passes the simple alimentary canal ; 
the slender oesophagus passing through an oblong muscular 
pharynx ; the expanded stomach (or intestine) occupying most 
of the body cavity. There is a small intestine, from which the 
anus opens at the base of the furea, on the dorsal side. 

Several naturalists have detected a water-vascular system 
somewhat like that of the Rotifera, but according to Zelinka 
it differs in many points. The canals are much convoluted, 



214 J. MURRAY ON GASTROTRICHA. 

and possess only one vibrating cell corresponding to the series- 
of flame-cells of Rotifera ; there is no contractile vesicle, and the 
canals open independently on the ventral side and have no 
connection with the intestine. 

While the eggs are frequently conspicuous, and their develop- 
ment may be conveniently studied, the sexual system is little 
known. Zelinka distinguishes paired ovaries. If the supposed 
male organs are such the Gastrotricha are hermaphrodite. 

Zelinka recognises in the alimentary canal the following parts : 
mouth, oesophagus, stomach, intestine with rectum and anus. 

There is a well-developed muscular system, and the brain and 
nervous system are similar to those of the Rotifera. 

Haunts and Habits. 

The Gastrotricha are found mainly in ponds, oftenest among 
the bottom sediment or vegetation. They rarely occur on mosses, 
except the permanently moist aquatic kinds. A few (at least 
one species, C. marinus) live in the sea. 

They are much less common, even in ponds, than the 
Rotifers and Water-bears. You cannot go out to collect 
assured of getting some you must trust to casual occurrences 
when studying other things. 

There are no special methods of collecting them. They will 
occur among your Rotifers, but not if you collect in clear, open 
water. Perhaps the likeliest means to obtain some is to wash 
aquatic weeds Myriophyllum, Fontinalis, Lemna, etc. 

If you wish to preserve them it can easily be done. As they 
are not contractile, they can be killed without previously 
narcotising by osmic acid, when they retain the natural shape.. 
They can be mounted in fluid cells by Rousselet's method, but 
formalin of the strength used for Rotifers is not a suitable 
medium, as it produces subsequent distortion. Some better 
medium has yet to be found. 

They appear to have only one habit, that of eating. They 
ar; always in motion, some slowly, some quickly, and always 
seem to be nosing for food. Yet they are not greedy eaters, but 
pick daintily here and there. As they creep along over the weeds 
they give the impression of active intelligence proportioned to- 
their needs. 



j. murray on gastrotricha. 21> 

Historical Sketch. 

As a history would be little more than the bibliography 
arranged chronologically, it need not take up much space. 

So far as my knowledge goes, the first notice of an animal of 
this order is by Joblot (32) 1718, who figures (Plate 10, fig. 22) 
his " poisson a la tete en trefie," which is the animal now known 
as Ichthydium. 

Corti 1774 (10) speaks of an " animaluzzo molle," and figures 
it, which Ehrenberg thinks may be a Chaetonotus. 

Eichhorn 1781 (20) figures (Plate 2, fig. R) what may have 
been a Chaetonotus. 

These were the pioneers, who bestowed no binomial desig- 
nations, but, before either Eichhorn or Corti, Miiller had in 1773 
(42) given three such names, the first, Cercaria podura, still 
persisting as Ichthydium podura. 

Many of the pre-Ehrenbergians bestowed various names on 
Gastrotrichs, usually only in attempts to classify, not describing 
supposed new species : Schrank 1776 (53) Brachionvs pilosus ; 
Lamarck 1815 (34) Furcocerca ; Bory 1824 (3) Leucophra, 1826 
(4) Diceratella ; Ehrenberg's first attempt, Hemprich and Ehren- 
berg 1828 (29) was Diurella podura (= Ichthydium). 

Ehrenberg did not notably advance the knowledge of this 
order, but he described two new species besides others, which are 
not now recognised as Gastrotrichs. 

After Ehrenberg came a rather barren period leading on to 
quite modern times: Dujardin 1841 (16), Gosse 1851 (23) and 

1864 (24), Schultze 1853 (55), Schmarda 1861 (52), Metchnikoff 

1865 (41), Tatem 1867 (61). The only works of any importance 
in this period are Gosse's and Metchnikoff's. 

Modern times may be said to begin with Daday in 1882 (11), 
and the principal workers have been Daday 1897 (12), 1905 (14), 
1910 (15); Collin 1897 (8), 1912 (9); Stokes 1887 (57) (59); 
Zelinka 1889 (71); Voigt 1904 (68); Lauterborn 1893 (35); 
Griinspan 1908 (26); Marcolengo (40) (72). 

Classification. 

The classification of the Gastrotricha is in an unsatisfactory 
condition. They are difficult animals to classify. I sympathise- 
with the efforts authors have made to introduce order into the- 



216 J. MURRAY ON GASTROTRICHA. 

group, and will not attempt to modify the generic arrangement, 
beyond shifting about some of the species. I am not qualified to 
deal with the question, but as some little assistance to students 
1 shall point out some apparent shortcomings of the prevailing 
classification. 

The three fork-tailed genera, Ichthydium, Chaetonotus and 
Lepidoderma, are separated on very slight characters, as Stokes 
(57) recognised in " lumping " them all together. Ichthydium 
has neither plates nor dorsal bristles ; Lepidoderma has scales, 
but is supposed to have no bristles ; Chaetonotus has bristles, 
and may have scales. So if an Ichthydium or a Lepidoderma 
possesses any dorsal bristles it becomes a Chaetonotus. How 
many bristles are necessary ? Some so-called Lepidoderma have 
a very few bristles. L. loricatus, Stokes, has no bristles, while 
a variety has four near the tail. 

Authors have made the matter worse by entirely disregarding 
the generic definitions, even those made by themselves. Thus 
Zelinka's Lepidoderma was instituted first to contain Dujardin's 
C. squammatus, which was described in these terms, " Revetu 
en dessus de poils courts, elargis en maniere d'ecailles pointues 
regulierement imbriquees," and which is thus a true Chaetonotus, 
following Zelinka's own definition. 

The possession or not of scaly armour is surely itself more 
important than the presence or not of bristles on the scales, 
but the character has not been used in classification quite 
rightly, for the scales are after all only the enlarged bases of 
the hairs, and there is every gradation from a slightly enlarged 
insertion to large imbricated scales. 

Authors have further confused matters by professing to identify 
a,s the species of the earlier authors animals which are quite 
different from their descriptions and figures. This is pernicious, 
as the practice nullifies the meaning of language, however 
precisely used. It may be admitted that the descriptions of 
Muller and Ehrenberg are insufficient to distinguish their species 
from the numerous similar species now recognised. But the 
species must either be dropped as " insufficiently described," or, 
if we profess to recognise them, it must be in animals possessing 
at least the characters ascribed to them by their discoverers. 

Ehrenberg has many faults, among which I reckon not 
least the insufficiency of his descriptions. Frequently these 



J. MURRAY ON GASTROTRICHA. 217 

contain no single distinctive character, and if it were not for 
his figures their recognition would be impossible. But he was 
not a slipshod observer, and when he happens to mention a 
distinctive feature I have no doubt the animal observed possessed 
it. Thus when he distinguishes C. maximus from C. larus by 
its dorsal bristles of equal length, we must give him the credit 
of supposing that his animal looked like that, unless naturalists 
agree that no such animal exists a difficult thing to prove. 
There are species with the dorsal bristles approximately of equal 
length, and so Gosse is not justified in identifying as C. maximus 
a species having the posterior bristles much longer. 

In the separation into larger groups, sub-orders, or families, 
the group has been equally unfortunate. The classification by 
Fraulein Griinspan (26) recognises three sub-orders : 

Suborder I. Euwhthtdina, having a forked tail. 

II. Pseudopodisa, having an apparently forked tail. 
III. Apodixa, without a forked tail. 



55 
55 



I am unable to grasp the distinction between a forked tail and 
an apparently forked tail, and the Apodina include one genus 
(Stylochaeta) which has a forked tail ; minute certainly, but is a 
small tail not a tail ? 

Zelinka's (71) classification is consistent, but the more puzzling 
genera were not discovered when he wrote. He recognises two 
sub-orders, and, I should suppose, three families, though he only 
names two : 

I. Sub-order : Euichthydina, having a "furca." 

1. Family Ichthydidae, without bristles. 
Genera Ichthydiu'ni and Lepidoderma. 

2. Family Chaetonotidae, with bristles. 
Genera Chaetonotus and Chaetura, 

II. Sub-order: Apodina, without a "furca." 
Genera Dasydytes and Gossea. 

Collin (9) follows Zelinka's classification, naming the family 
Dasydytidae, which includes all the Apodina, and allocating 
all the genera described since Zelinka's work to places in the 
three families. 

All this is very unsatisfactory. The anomalies of these systems 
I have pointed out as exemplified in that of Fraulein Griinspan. 

Journ. Q. M. C., Series II. No. 73. 15 



218 J. MURRAY ON GASTROTRICHA. 

I have no better to offer, so I suggest that we leave classification 
on broad lines till we know more, and classify in genera only. 

These have also been badly handled. Ehrenberg's two genera, 
Ichthydium and Chaetonotus, will serve as a beginning of classi- 
fication till we find something better. The distinction between 
hairy and smooth is not important, and in many genera of 
animals both types occur -e.g. Macrobiotus among Tardigrada, 
but among Gastrotricha, if we are to have divisions at all, 
we must be satisfied with very trivial characters. Miiller's 
Cercaria poduva, which became the type of Ichthydium, was 
probably a composite diagnosis, as some of his figures show 
bristles. I have shown the unsatisfactory treatment of his genus 
Lepidoderma by Zelinka, but, if his generic characters were 
regarded in allotting species to it, it might serve as a temporary 
artificial genus till we see our way out of the muddle. 

Ehrenberg's obsession for symmetry in classification led to 
many obviously false associations of species, and tyrannised over 
naturalists till a late period, even as late as 1864 affecting 
Gosse. It is curious now to regard the genera once included 
in the Gastrotricha Ptygura, Glenojihora and to think that 
Sacculus and Taphrocampa were originally described by Gosse 
as Gastrotrichs. 

Key to the Genera. 

A. Without a furca. 

1. Body with long bristles .... Dasydytes. 

2. Body without long bristles . Anacanthoderma. 

3. Head with antennae . Gossea (G. antennigera). 

B. Furca minute or obscure. 

4. Furca minute, large barbed bristles . Stylochaeta. 

5. Furca obscure, short ..... Setopus. 

6. Head with antennae . . . Gossea (two species). 

C. Furca conspicuous, body with bristles. 

7. Furca simple, bristles pointed . . Chaetonotus. 

8. Furca simple, bristles expanded at apex Aspidiophorus. 

9. Furca twice furcate ..... Chaetura. 

D. Furca conspicuous, body without bristles. 

10. Body with scaly armour . . . Lepidoderma. 

11. Body without scales .... Ichthydium. 



J. MURRAY ON GASTROTRICHA. 219 

Note. Anacanthoderma can hardly be separated from Dasy- 
dytes, as the only species is described as having some bristles. 
Aspidiophorus is a Chaetonotus, having the bristles enlarged at the 
apex, scarcely a generic distinction, as those having enlarged 
bases are not considered generically distinct. Gossea is usually 
put in the Apodina, but Daday's two species possess the furca, 
and Gosse's antenniger with its caudal bundles of setae may be 
said to possess the homologue of the furca. Setopus primus 
is scarcely distinguishable, even as a species, from Dasydytes 
bisetosus Thomp., yet from the possession of a slight medial 
depression at the posterior end it has technically a furca, and 
becomes a distinct genus. 

List of all Species which have been Described. 

In alphabetical order, and under the original generic names, 
with critical notes on synonymy and specific values. 

1910. Anacanthoderma punctatum Marcolongo (40). 

1902. A sp)idonotus paradoxus Yoigt. (65). Now a genus Aspidio- 

phorus. 
1865. Cephalidium longisetosum Met. (41). Is a Dasydytes. 
1773. Cercaria podura Mull. (42). Now the type of Ichthydium 

Ehr. 
1887. Chaetonotus acanthodes Stokes (57). 
1887. C. acanthophorus Stokes (57). 

1903. C. arquatus Voigt. (67). 
1832. C. breve Ehr. (16). 
1889. C. brevispinosus Zel. (71). 
1901. C. chuni Voigt. (64). 

1887. C. concinnus Stokes (57). Is a Lejndoderma. 

1910. C. decemsetosus Marco. (40). 

1905. C. dubius Dad. (14). 

1887. C. enormis Stokes (57). 

1905. C. erinaceus Dad. (14). 

1887. C.formosus Stokes (59). 

18(54. C. gracilis Gosse (24). 

1905. C. heterochaetus Dad. (14). 

1910. C. hirsutus Marco. (40). 

1865. C. hystrix Met. (41). 



220 J. MURRAY ON GASTROTRICHA. 

1910. G. larvides Marco. (40). 

1902. C. linguaeformis Voigt. (66). 

1867. G. longicaudatus Tatem (61). Is an Ichthydium. 

1887. G. longisjnnosus Stokes (57). 

1887. G. loricatus Stokes (57). Is a Lepidoderma. 

1893. G. macracanthus Laut. (35). Is probably G. entzii 

(Dad.). 
1889. C. macrochaetus Zel. (71). 

1904. G. mwrinus Giard. (22). 

1832. G. maximus Ehr. (18). 1 

1910. G. minimus Marco. (40). 

1908. C. multispinosus Griin (26). Is C. tabnlatum Schm. 
1901. G. nodicaudus Voigt. (63). Very like G. entzii (Dad.). 
1910. C. nodifurca Marco. (40). Very like G. entzii (Dad.). 
1887. G. octonarius Stokes (57). 

1897. G. ornatus Dad. (12). 

1910. C. paucisetosus Marco. (40). 

1889. C. persetosus Zel. (71). j 

1909. C. ploenensis Voigt. (69). 

1905. C.pusillus Dad. (14). ] 
1887. C. rhomboides Stokes (57). Is probably 0. entzii (Dad.). 
1865. C. schidtzei Met. (41). 

1901. C. serraticaudus Voigt. (63). 

1889. C. similis Zel. (71). | 

1909. C. simrothi Voigt- (69). 

1887. C. spinifer Stokes (57). ] 

1887. C. spinidosus Stokes (57). 

1864. C. slackiae Gosse (24). 
1841. C. squammatus Dnj. (16). 

1902. C. snccinctus Voigt. (66). 

1887. C. sulcatus Stokes (57). Is an Ichthydium. 

1908. C. tenuis Griin. (26). 

1902. C. uncinus Voigt. (66). 

1908. C. zelinhai Griin. (26), 

1865. Chaetura capricornia Met. (41). 
1913. C. piscator Murray. (Described in this paper for first 

time.) 
1851. Dasydytes antenniger Gosse (23). Now the genus Gossea. 
1891. D. bisetosus Thomp. (62). 
i909. D. dubiiis Voigt. (69). 



J. MURRAY ON GASTROTRICIIA. 221 

1909. B.festhians Yoigt. (69). 

1851. D. goniathrix Gosse (23). 

1909. D. ornatus Voigt. (69). 

1910. D. pa ucisetosus Marco. (40). 
1887. D. saltitans Stokes (59). 

1901. D, stylifer Yoigt. (64). Is a Stylochaeta. 

1893. D. zelinkai Laut. (35). Seems to be D. goniathrix Gosse. 

1886. Ichthydium bogdanovii Schim. (51). Is a Chaetonotus. 

1905. /. crassum Dad. (14). 

1908. /. cyclocephalum Griin. (26). 

1882. /. entzii Dad. (11). Is a Chaetonotus. 

1901. I.forcipatum Voigt. (64). 

1861. I . jamaicense Schin. (52). Is a Chaetonotus. 

1897. /. macrurum Collin. (8). 

1865. /. ocellatum Met. (41). 

1861. /. tabulatum Schm. (52). Is a Chaetonotus. 

1908. /. tergestinum Griin. (26). 

1905. Gossea fasciculata Dad. (14). 

1905. G. pauciseta Dad. (14). 

1897. Lepidoderma biroi Dad. (12). Is probably C. entzii (Dad.). 

1905. L. elongatum Dad. (14). Is probably C. entzii (Dad.). 

1910. L. hystrix Dad. (15). Is probably C. entzii (Dad.). 

1890. Polyarthrafusiformis Spencer (56). Now genus Stylochaeta. 

1908. Setopus primus Griin. (26). Scarcely differs from Dasydytes. 

1776. Trichoda larus Mull. (43). Now Chaetonotus larus. 

Identification of Species. 

It was my ambition to accompany this paper by a key to all 
the species hitherto described, so that the student might identify 
them all, or at least know what characters they were supposed 
to have. I found the task beyond my powers, for not only are 
there a number of descriptions which I have been unable to 
consult, but many of the diagnoses are such that to make use 
of the characters given in them would be actually misleading. 

This is especially true of negative characters. Certain species 
are described as having the body covered with scales, others as 
having some or all of the bristles barbed or with supplementary 
points. It must not be assumed that species not thus character- 
ised do not possess those characters. Both are structures 



222 J. MURRAY ON GASTROTRICHA. 

excessively difficult to see, and the authors of species may have 
overlooked them. 

There is no more definite character for distinguishing species 
of Chaetonotus than the form of the dorsal plates, if one could 
only see them, but nothing has astonished me more than the 
utter invisibility of those plates, till some accident, such as finding 
an empty skin or mutilated specimen, has revealed them. 

As I have put some work into the preparation of this key, and 
do not wish to throw it away, I have made some use of the 
material by indicating for the genus Chaetonotus certain groups 
of species characterised by the possession of some common 
feature. 

Chaetonotus. 

Body covered by Plates or Scales. 

G. acanthodes, acanthophorus, arquatus, brevispinosits, chuni, 
entzii, erinaceus, heterochaetus, hystrix, larus, linguaeformis, macro- 
chaetus, maximus, octonarius, ornatus, persetosus, ploenensis, 
pusillus, schultzei, serraticaudits, similis, simrothi, spinifer, squam- 
matus, succinctus, tabidatus, tenuis, uncinus, zelinkai. 

Stated to have no Plates. 
G. enormis, formosus. 

Nothing said about Plates. 

G. bogdanovii, dubius, gracilis, jamaicense, longispinosus, 
marinus, slackiae, spi?iulosus. 

With Cephalic Shield. 

C. entzii, erinaceus, formosus, maximus, ornatus, persetosus, 
pusillus, schultzei, tenuis, zelinkai. Not noted for the other 
species. 

Head not Lobed. 

G. bogdanovii, dubius, jamaicense, marinus, ornatus, slackiae, 

tabidatus. 

Head Three-lobed. 

G. brevispinosits, chuni, erinaceus, formosus, heterochaetus, 
hystrix, larus, linquaeformis, macrochaetus, pusillus, schultzei, 
serraticaudus. 



j. murray on gastrotricha. 223 

Head Five-lobed. 

C. acanthophorus, arquatus, eno?"mis, gracilis, longispinosus, 
maximus, octonarius, persetosus, ploenensis, similis, simrothi, 
spinulosus, squammatus, succinclus, tenuis, uncinus, zelinkai. 

All Bristles with Supplementary Points (Barbs). 
C. chuni, erinaceus, hystrix, schultzei, similis, spinifer. 

Some Bristles Barbed. 

C. acanthophorus, enormis, heterochaetus, longispinosus, macro- 
chaetus, octonarius, persetosus, spinulosus, zelinkai. All the 
others are supposed to have simple unbranchecl bristles. 

Having Series of Larger Thicker Bristles. 

C. acanthodes, acanthophorus, bogdanovii, brevispinosus, dubius, 
enormis, heterochaetus, longispinosus, macrochaetus, octonarius, 
ornatus, ploenensis, persetosus, similis, spinifer, spinulosus, suc- 
cinctus, tenuis, uncinus, zelinkai. 

Posterior Bristles Progressively Longer (exclusive of 
the larger bristles above noted). 

C. arquatus, chuni, entzii, erinaceus, hystrix, larus, macro- 
chaetus, ornatus, pusillus, schultzei, similis, tenuis, zelinkai. 

Bristles equal or not Noticeably Longer Posteriorly. 

C. brevispfinosus, dubius, formosus, gracilis, heterochaetus, 
jamaicense, linquaeformis, marinus, maximus, serraticaudus, sim- 
rothi, slackiae, squammatus, tabulatus. 

Notes on Some Species I have Seen. 

I have in some of my faunistic lists noted Chaetonotus larus 
and Ichthydium podura, but these records have the same value 
as nearly all such records i.e. none. 

At various times I have made studies of species which I could 
not identify with the assistance of the literature at my disposal. 
After reviewing nearly all the literature, and taking all tha 



224 J. MURRAY ON GASTROTRICHA. 

diagnoses at their face value, it appears that several of these 
species differ from any of those described in the works known 
to me. 

I would have dealt with these in the usual way and described 
them as new species, but just as I was finishing this paper Mr. 
Harring of Washington was good enough to call my attention 
to a paper by Marcolongo which I had overlooked (40). In that 
paper there are described a number of new species of Chaetonotus, 
as well as a new family and genus. 

Mr. Harring has kindly transcribed the descriptions, which 
appear to be better than such things usually are, but as they 
are unaccompanied by figures no certain identification is possible. 
I consider all descriptions of animals in this group unaccompanied 
by figures as insufficient, but we are promised figures in a forth- 
coming work by the same author. 

In the circumstances I have no alternative but to withdraw 
my new species in the meantime, but there can be no harm in 
figuring and describing them as animals I have actually seen. 

Several of these are figured on the plate, in company with 
others which I do nob suppose to be new species. 

The species of Chaetura I can describe with an easy mind, as 
no one since Metchnikoff has ever described a species of this 
genus. 

Ichthydium sp. (PL 19, fig. 23). 

A graceful little animal, with very slender neck, deeply 
trefoliate head and long furca. The branches of the furca 
are close together at the base, and diverge, tapering to points. 
No tactile setae are noted, but the animal probably had them. 
Length about 130 fx. 

Habitat. Amongst Sphaynum, Fort Augustus, Scotland, 1904. 

It is a good deal like Joblot's " poisson a la tete faite en trefle," 
which some have identified as /. podura. But what was /. podura 
like ? Various animals have been figured by authors under that 
name, stout animals and thin animals, with long, slender furca 
or with little blunt knobs. Usually they do not appear to have 
gone back to Miiller, or even to Ehrenberg, to find what podura 
was like. If they had they would have found it was like various 
things. Miiller's podura possessed bristles (in some figures), and 



J. MURRAY ON GASTROTRICHA. 225 

so ought to go into Ehrenberg's genus Chaetonotus. Its furca 
was somewhat like the animal I have figured. Ehrenberg's had 
a different furca. 

Lepidoderma sp. (PI. 10, fig. 29). 

A very small animal, with five-lobed head, apparently 
rhomboid scales, and a short furca with diverging branches. 
Long, tactile setae on the head. Length, 50 to 60 /x. 

The small size might lead to the supposition that the animal 
is young. In the only instance in which I have seen a Gastrotrich 
hatch out of the egg the young was of the full adult length of 
the species. It had only to eat and fill out. From this I suppose 
that Gastrotricha, like many Rotifera, do not grow appreciably 
in length. 

I say the scales are " apparently ' rhomboid, because the 
regular double diagonal arrangement in rows might give rise 
to this appearance although the scales were of some other 
form. 

Chaetonotus sp. (PI. 19, figs. SlaSlb). 

Of medium size ; trunk oval, neck well marked, head slightly 
elongated, five-lobed, without cephalic shield. Mouth nearly 
terminal, with tuft of hairs. 

The bristles on the head and neck are excessively short and 
fine. At the front of the trunk they become abruptly longer 
and thicker (though still short) and progressively longer 
posteriorly. Near the base of the furca there are some half- 
dozen bristles longer and thicker than any others. None of the 
bristles are barbed. 

The scales from which the hairs spring are elongate hexagons, 
with the angles so rounded off that they are almost oval. They 
are arranged in regular diagonal rows, and are separated at 
their bases by spaces about equal to the width of the scales. 

The furca is short, the branches diverging, then converging 
(enclosing a rhomboid place), obtuse. 

No plates can be seen on the head or neck. It is the only 
species I have seen in which the scales are visible and conspicuous 
in a specimen in good condition. 

Habitat. Scotland. 



226 J. MURRAY ON GASTROTRICHA. 

t 

Chaetonotus entzii (Dad.)? (11) (PL 19, fig. 26). 

A large animal, 250 to 300 jul and upwards in length. Head 
obscurely 3-lobed, with two anterior processes, and two others at 
posterior angles. Body long, nearly parallel-sided, covered with 
apparently rhomboid scales, in diagonal rows, and fine short hairs, 
gradually becoming longer posteriorly. Furca very long, nodose 
(about twenty nodes in the length), widely divergent at base where 
separated by small sulcus, less widely divergent above base. 

Habitat. Pond in the Praca Republica, Rio de Janeiro, Brazil ; 
several specimens. 

About eight species of long-furcate nodose Gastrotrichs have 
been described, which have all a suspiciously strong family likeness. 
Some of these are certainly synonymous, their authors being 
unaware of the existence of the other species. Daday, who is 
responsible for the greater number of them, professes to draw 
distinctions, but he is not very convincing, and moreover I have 
found the animal here described to be extremely variable. 

Daday first described entzii as an Ichthydium, although it had 
the characters of Chaetonotus. Later he described similar forms 
as Lepidoderma, although some of them at any rate did not fit his 
genus. Some he compared with entzii and with rhomboides Stokes, 
noting that some had not the spines on the head, some had the 
furca hairy, others smooth, etc. I cannot pretend to sort oat all 
of these here, but content myself with pointing out the family 
resemblance. 

Those I found in Rio had the hairs extremely variable, in some 
very short, in others not visible at all. I could not doubt that 
these were all one species, as I could see no other differences 
whatever. The various species having long nodose furca will be 
found noted in the list of all described species. 

Chaetonotus sp. (PI. 19, fig. 30). 

Large. Head short, 5-lobed, with cephalic shield, neck slightly 
marked. Body clothed with simple hairs in about fifteen or 
sixteen longitudinal rows, progressively longer posteriorly. Scales 
like spear-heads, very like those of C. larus (fig. 9). The outline 
of the body appears crenulate, with very prominent papillae in 
the narrow part above the furca. About eight longer setae close 



J. MURRAY ON GASTROTRICHA . 227 

to the furca, springing from the papillae. Fnrca longish, widely 
divergent, obtuse pointed. 

Habitat. Praca Republica, Rio de Janeiro. The original larus 
is probably not now recognisable, but modern authors have 
defined it as an animal with scales as in fig. 9, and about eleven 
longitudinal rows of them. This has more numerous rows. As 
far as can be judged from the description without a figure, this 
species is very like C. laroides Marco., but that is said to have the 
scales truncate posteriorly. 

It is to be noticed that these very destinctive scales are quite 
invisible in living or well-preserved specimens. I have only 
managed to see them in empty, partly shrivelled skins. 

Chaetonotus sp. (PI. 19, fig. 34). 

Of moderate size. Head obscurely 3-lobed, with large cephalic 
shield. Body covered with long, widely out-curved bristles, all 
barbed, in few rows (six seen in dorsal view) springing from 
obscure but large hemispherical scales. Close to the furca nine 
very long, recurved, barbed bristles, three dorsal, six lateral. 
Branches of furca long, separated by sulcus at base, outcurved, 
knobbed. 

Habitat. Sydney and New Zealand ; a very similar form in 
Rio, Brazil. 

The most obvious character is the widely spreading bristles. 
Even those nearest the cephalic shield are long, but they are 
progressively longer posteriorly till near the furca, when a few 
quite short bristles intervene between the longest dorsal bristles 
and the special large ones at the furca. 

Chaetonotus sp. (PI. 19, fig. 35). 

Of moderate size, relatively broad and squat. Head rounded, 
5-lobed. Neck well-marked, short. Trunk parallel-sided. Body 
covered with apparently rhomboid scales, each bearing a short 
spine or scale. Furca short, diverging, then converging (enclosing 
a rhomboid space), the basal portion scaly, the apical portion 
smooth. There are long tactile setae on the head. 

The general form is like that of Ichthydium ocellatum Met. 
[Lepidodei'ma ocellatum Zel.). I saw nothing like the eye-spots 
ascribed to both those animals. 



228 J. MURRAY ON GASTROTRICHA. 

As there are no type specimens, and only MetchnikofTs descrip- 
tion to go by, there is no justification for transferring his species 
to the genus Lepidoderma, as Zelinka does. It is either an 
Ichthydium Ehr. or insufficiently described and unrecognisable. 

Zelinka's animal may be the one which I here figure. If so 
it seems to me that the little triangular scales or spines are 
homologous with the bristles of Chaetonotus, and not with the 
scales of Lepidoderma, and so it should be placed in the former 
genus. 

Habitat. Summit of Ben Lawers, Scotland, among moss, 1905. 

Chaetura piscator sp. now (PI. 19, fig. 33). 

Specific characters. Small ; head elongate, egg-shaped, fringed 
with long setae ; neck moderately constricted ; body spindle- 
shaped ; each branch of furca forked, branches equal ; trunk 
bearing at least four longitudinal series of fine bristles shaped like 
fish-hooks, and some straight setae near the furca. 

General description. Length 150 /x, head 50 /x long by 36 /x 
wide, trunk 30 fx wide, branches of furca about 12 jx ; hooks 
project about 15 fx above the surface. 

The head is the widest part of the body. It is fringed by long 
straight hairs or setae, and bears some larger movable setae which 
appear to have a tactile function. The neck is slightly constricted, 
but has a swelling. The dorsal hairs are shaped exactly like fish- 
hooks, without their barbs. They spring out at nearly right 
angles to the skin, curve round in the posterior direction, and 
nearly touch the skin at their tips. I distinguished four rows 
of them, but in dealing with such excessively fine structures 
it is not well to state hard-and-fast numbers. Four of the 
straight setae could be seen dorsally, close by the tail ; the four 
branches of the furca are nearly equal, slightly curved, and have 
blunt tips. 

Technically this is a Chaetura, having the branches of the furca 
furcate, although in MetchnikofTs type species, G. capricornia, 
they are not properly furcate, but bear little branches on the 
inner side. As in the type, the head is broader than the trunk 
and there are stiff bristles over the tail. The fishhook-like setae 
distinguish it from all other known Gastrotrichs. 

Habitat. Amongst moss, Shetland Islands, 1906. 



j. murray on gastrotricha. 229 

Bibliography. 

An asterisk * indicates works in which new species are described. 

The works of any importance number scarcely more than a 
dozen. They are Ehrenberg, 1838 (19); Gosse 1851 (23), and 
1864 (24); Metcbnikoff 1865 (41); Stokes 1887 (57); Daday 
1882 (11), 1901 (13), 1905 (14), 1910 (15); Zelinka 1889 (71); 
Giard 1904 (22); Yoigt 1904 (68); Griinspan 1909 (26); Collin 
1912 (9). 

With these works the student will have everything he requires, 
except a few descriptions of doubtful new species. 

Ehrenberg, 1838, summarises the work of the pioneers, and 
originates a classification. Fraulein Griinspan, 1909, gives the 
fullest systematic account of the group. Zelinka, 1889, is far and 
away the best work on the subject, being a painstaking and 
minute study ; but much has been added to our knowledge since his 
memoir appeared. Collin, 1912, is simply a compilation, but a 
useful one. The others noted above are the principal systematic 
works, containing descriptions of many species. 

1. Archer, W. In Quart. Joum. Micr. ScL, 14, p. 106, 1874. 

Exhibited at Dubl. Micr. Club, C. maximus, C. gracilis, 
and D. antenniyer ; all found in Ireland. Note that the 
last species can elevate and depress its antennae. 

2. Barrois, T. Comptes rendus, July 1887. Trans, in Ann. 

Mag. Nat. Hist., xx., p. 365, 1877. 

A segmental worm, having the appearance of Ichthy- 
dium, but differing much in structure. Probably related 
to Hemidasys, Turbanella, Zelinkia, Philocyrtis, which are 
not Gastrotricha. 

3. Bory de St. Vincent. Encycl. method., Paris, 1824. 

Furcocerca podura ( = Ichthydium) ; Zeucophrya larus 
( = Chaetonotus). 

4. Ibid. Essai des micr., 1826. 

Diceratella larus ( = Chaeto?iotus). 

5. Bryce, D. In letter to Fraulein Griinspan (vide 26, p. 228). 

Records C. zelinkai for England and Scotland. 

6. Butschli, O. Freilebende Nematoden u. d. Gattung Chae- 

tonotus. Zeit. fur wiss. Zool., 26, pp. 385, 390, etc., 1876. 
Classification and Anatomy. Good structural figures of 
C. maximus and C. larus. 



230 J. MURRAY ON GASTROTRICHA. 

7. Claparede, E. Misc. zool. III. nouveau genre de Gastero- 
triches. Ann. Sci. Nat., Ser. 5, vol. 8, p. 18, 1867. 

Hemidasys agaso gen. et sp. nov. Not a Gastrotrich, I 
think. 

*8. Collin, A. Rot. Gastro u. Entoz. Deutsch Ost-Afrika, 4, p. 9, 
1897. 

/. macrurum sp. n. A somewhat meagre description, 
from figure drawn by Stuhlman. 

9. Ibid. Gastrotricha. In Susswasserfauna Deutschlands, 
pp. 240-65, figs. 475-507. 

A good account of thirty-two German species, with 
many useful figures. No new species. 
10. Corti. Osser. micr. sulla Tremetta, p. 89, PI. 2, 1774. 

Ehrenberg thirks the " animaluzzo molle " may have 
been C. maximus. I have not seen the work. 
*11. Daday, E. Ichthydium entzii. 

Termes. Fiiz., pp. 231-52, PI. 3, 1882. 

New species ; full description and good figures. Seems 
to be the first appearance of a much-described animal 
which is almost certainly the same as Stokes' C. rhom- 
boides, and is probably also Yoigt's C. nodicaudus 
and Daday's own L. hystrix, L. elongatum and L. biroi, 
as well as C. macracanthus Laut. I found the animal 
in Rio de Janeiro, and noted that the dorsal hairs 
vary greatly in length and may be absent, so that 
the species is both Chaetonotus and Lepidoderma on 
occasion ! 

*12. Ibid. Uj-Guineai Rotatoriak. Math. es. Termes. Ertes., 
vol. 15, pp. 145-48. (In Hungarian.) 1897. 
New species C. orno.tus and L. biroi. 

13. Ibid. Mikr. Siisswasserthiere aus Deutsch Neu-Guinea. 
Termes. Filz., 24, 56 pp., 3 plates, 1901. 

Description and figures of the two new species of his 
previous paper (1897). 

*14. Ibid. Susswasser-mikrofauna Paraguays. Zoologica, 18, 
pp. 72-86, Pis. 5-6, 1905. 

Eight new species I.crassum, L. elongatum, C.pusillus, 
C. dubius, C. erinaceus, C. heterochaetus, G. fasciculata, 
G. paaciseta. 



J. MURRAY ON GASTROTRICHA. 231 

*15. Ibid. Susswasser-mikrofauna Deutsch Ost-Afrikas. Zoo- 
logica, 23, pp. 56-9, PI. 3, 1910. 
New species L. hystrix. 
*16. Dujardin, F. Hist. nat. des Zoophytes Infusoires, pp. 515- 
69, PL 18, figs. 7-8, 1841. 

New species C. squamniatus. 
17. Ibid. Sur un petit animal marin (l'Echinodere). Ann. Sci. 
Nat., Ser. 3, vol. 15, p. 158, PI. 3, 1851. 
Once classed with the Gastrotricha. 
*18. Ehrenberg, C. J. Organ, in d. Richtuny d. kleinsten Raumes, 
2nd Part, Berlin, 1832. 

Descriptions (perhaps not his earliest) of /. podura, 
C. maximus, C. larus, C. breve. 

19. Ibid. Die Infusionsthierchen, pp. 386-90, 1838. 

Redescribes the same four species as in 1832. 

20. Eichhorx, I. C. Naturgeschichte der kleinsten Wasserthiere, 

p. 35, PI. 2, fig. r, 1781. 
Probably a Chaetonotus. 

21. Florentin, R. Faune des mers salees. Ann. Sci. Nat. 

(Ser. 8), 10, p. 272, 1899. 

Records Lepidoderma ocellatam from salt water. 
*22. Giard, A. Faunule caracteristique des sables a Diatomees. 
C. R. Soc. Biol, pp. 1061-5, 1904. 

New species C. marinus. Also new genera Zelinkia 
(sp. Z. plana) and Philocyrtis (sp. P. monotoides), which 
are very doubtful Gastrotricha. 
*23. Gosse, P. H. A Catalogue of Potifera found in Britain. 
Ann. Mag. Nat. Hist., Ser. 2, vol. 8, p. 198, 1851. 

New genus Dasydytes, and new species D. goniathrix 
and D. antenniger ; no figures. Saccidus viridis described 
as a Gastrotrich. 
*24. Ibid. The hairy-backed Animalcnli. Intell. Obs., V., 
pp. 387-406, 2 plates, 1864. 

New species C. slackiae, C. gracilis. 
Taphrocampa new genus, described as a Gastrotrich. 
25. Grimm, O. A. Fauna im baltischen Meere (is a German 
rendering of the Russian title). Arb. d. St. Peter. Naff 
Ges., 8, p. 107, 1877. 

Gastrochaeta ciliata new genus and species. No figure 
given. In a footnote he compares the animal with various 



232 J. MURRAY ON GASTROTRICHA. 

species of Desmoscolex, so it is probably not a true 
Gastrotrich. 
*26. Grunspan, Therese. Systematik cler Gastrotrichen. Zool. 
Jahrb., pp. 214-56, 1908. 

A comprehensive synopsis of all known species. Seventy 
admitted species ; six new species and a new genus /. terges- 
tinum, I. cyclocephalum, C. zelinkai (and var. gra.censis), C. 
tenuis, C. midtispinosas, Setoptcs primus(gen. et sp. nov.). 

27. Ibid. Die SUsswasser-Gastro-trichen Europas. Eine zusam- 

menfassende Darstellung ihrer Anatomie, Biologie und Sys- 
tematik. Ann. Biol. Lacustre, Bruxelles, vol. 4, pp. 21 1 365 ? 
61 figs. 

28. Hartog, M. Rotifera Gastrotricha and Kinorhynchia. 

Cambridge Nat. Hist., vol. 2, p. 232, etc., 1896. 

A good account and figures of seven known species. 

29. Heinrich u. Ehrenberg. Symbolae physicae. Evertebrata. 

I. Phytozoa, Plates. Berlin, 1828; text, 1831. 

PI. I., fig. 11, Diurella podura (= Ichthydium). 
*30. Hlava, S. Syst. Stell. v. Polyarthra fusiformis Spencer. 
Zoo. Anz., 28, pp. 8-9, December 1904. 

New genus Stylochaeta (sp. S. fusiformis Spencer). 

31. Imhof, 0. Tiefseefauna SUsswasserbecken. Zoo. Anz., 8, 

p. 325, 1885. 

Found C. maximus as an abyssal species in lakes. 

32. Joblot. Nouvelles Observations, p. 79, PI. 10, fig. 22, 1718. 

" Poisson a la tete faite en trefle " ( = /. podura). 

33. Kojevnikof, G. Faune de la mer Baltique orientale. 

Congres intern. Zool. II., Moscow, pp. 132-57, 1892. 
I have been unable to find this work. 

34. Lamarck. Hist. nat. des Animaux sans vertebre, p. 447, 1850. 

Furcocerca podura ( = Ichthydium). 
*35. Lauterborn, R. Rot. -Fauna d. Rheins u. s. Altwasser. 
Zool. Jahrb., 7, Syst., pp. 1^54-73, PI. 11, 1893. 

New species Dasydytes zelinkai, C. mawacanihus . The 
description shows D. zelinkai as a not very distinct variety 
of D. goniathrix Gosse. No figure is given. C. macra- 
canthus appears to be C. entzii Dad. 
36. Ibid. Die sapropelische Lebewelt. Zoo. Anz., 24, pp. 50-55, 
1901. 

Dasydytes zelinkai (see previous paper). 



J. MURRAY ON GASTROTRICHA. 233 

37. Lucks, R. Linaugebiet micr.-Wasserbewohner. Jahrb. West- 

preuss. Lehrver.f. Naturk., pp. 20-23 (1905), 1906. 
List of eight known species in West Prussia. 

38. Ibid. Neues aus d. Mikrofauna Westpreussens. Ber. West- 

preuss. Bot.-Zool. Ver., 31, pp. 141-2, 1909. 

Three additional known species in West Prussia. 

39. Ludwig, K. TJ. d. Ordnung Gastrotrichs. Zeit. far iviss. 

Zool., 26, pp. 219-25, 1875. 

A general work, dealing with systematic position, etc. 
List of thirteen known species. 
*40. Marcolongo, I. Primo contributo alio studio dei Gastro- 
trichi del lago-stagno craterico di Astroni. Monitore Zool. 
Ital. Firenze, 21, pp. 315-18, 1910. 

He gives no figures, but describes a new family 
Anacanthodermidae, a new genus linacanthoderraa, and 
eight new species Chaetonotus laroides, C. hirsutus, C. 
minimus, C. nodifarca, C. decemsetosus, C. 2)aucisetosus, 
Dasydytes imucisetosus, Anacanthoderma punctatum. 

I have not seen this paper, but received these particulars 

by favour of Mr. Harring, of Washington. (Vide No. 72.) 

*41. Metchnikoff, E. Wenig-bekannte niedere Thierformen. 

Zeit. fur wiss. Zool, 4, pp. 450-8, PI. 15, 1865. English 

trans, in Journ. Jlicr. Sd. (N.S. 6), pp. 241-52, 1865. 

New genera Chaetura (sp. capr worms), Cephalidium 
(= Dasydytes) (sp. longisetosum). New species Ichthy- 
dium oceUatum, C. hystrix, C schultzei. 
*42. Muller, O. F. Verm. terr. etfluv., pp. 66 and 79, 1773. 

New species Cercaria podura (= Ichthydiam), Trichoda 
acarus and T. anas (both now = C. larus). 
*43. Ibid. Prod. Zool. Dan., 1776. 

Trichoda lai'us ( = Chaetonotus). 

44. Ibid. Anim. infus.fluv. et marina, 1786. 

Trichoda larus ( Chaetonotus). 

45. Nitzsch. Infusorienkunde, 1817. 

Enchelys podura ( = Ichthydium). 

46. Norrikov, A. Y. K. sistematikie Gastrotiicha (Russian). 

Triid. Obs. Ahklim. Moskau, 6, 1907, pp. 309-47, PI. 10. 

I have not seen this paper, but Mr. Harring, who kindly 
furnished the reference, says it is largely a translation of 
Zelinka's paper (71) and contains little that is new. 
Journ. Q. M. C., Series II. No. 73. 16 



234 J. MURRAY ON GASTROTRICHA. 

47. Parsons, F. A. In the Quekett Journal for 1896-7 there 

occur some records of Gastrotricha found at the excursions 
of the Club. I do not know who made the actual iden- 
tifications, but the records are referred to in Mr. Parsons's 
name by various authors. 

48. Perrier, E. Traits de Zoologie, Fasc. 4, pp. 1534-9, figs. 

1103-5, 1897. 

A general account of six species, with some figures. 

49. Perty, M. Kleinste Lebensfovmen dev Schweiz, p. 47, 1852. 

A few remarks on the group and several known species. 

50. Pritchard, A. History of Infusoria, 1861. 

The earlier editions of Pritchard contain a few notes 
after Ehrenberg. In 1861 there is a fair account of the 
group. 
*51. Schimkewitsch, W. M. Neue Species Ichthydium. Nachr. 

K. Ges. Freunde d. Natuv., 50, 1886 (/. bogdanovii). 
*52. Schmarda, L. K. Neue wivbellose Thieve, i. 2, 1861. 

Describes two new species as Ichthydium /. jamaicense 
and /. tabulatum which are technically Chaetonotus, 
according to his own generic definition of Ichthydium. 

53. Schrank, P. v. P. Beitvdge ficv Natuvgeschichte, 1776. 

His Bvacliionus pilosus (Part III., PI. 4, fig. 32) is, 
according to Dujardin (16, p. 570, footnote), Chaetonotus 
lav us. 

54. Ibid. Fauna Boica, hi., pp. 90-91, 1803. 

Tvichoda lavus ( = Bvacliionus pilosus), T. anas. 

55. Schultze, M. Ueber Chaetonotus mid Ichthydium Ehr. 

Avcli. f. Anat. u. Phys., vi., pp. 241-54. 

New genus Tuvbanella, which I believe is not a 
Gastrotrich. 
*56. Spencer. On a new Rotifer, Polyavthva fusifovmis. 

This is a Gastrotrich, since made the type of a new 
genus, Stylochaeta, by Hlava (30). J. Q. M. C, 1890, p. 59. 
*57. Stokes, A. C. Observations on Chaetonotus. The Micro- 
scope (American), vol. 7, two parts, January and February, 
1887, pp. 1-9, PI. 1 ; pp. 33-43, PI. 2. 

One of the most considerable works on the group, in 
which a great many new species are described. They are 
all regarded as Chaetonotus, the earlier generic distinctions 
not being admitted. 



J. MURRAY OX GASTROTRICHA. 235 

New species 0. sulcatus, C. concinnus, C. loricatus, 
C. rhomboides, C. spinifer, C. acanthodes, C. octonarius, 
C. spinulosus, C. longispinosus, C. enormis, C. acantho- 
jjhorus. 

Apparently good figures are given of all of these species, 
and of species of other authors, but Stokes claims indul- 
gence for inaccuracies in all his figures. 
58. Ibid. Observations sur les Chaetonotus. Journ. de Microg., 
II, 3 parts, February, April, December, 1887, pp. 77-84, 
150-3, 560-6, PI. 1 and 2. 

Simply a translation of the American paper, with the 
same plates. 
*59. Ibid. Observation on a new Dasydytes and a new 
Chaetonotus. The Microscope, vol. 7, pp. 261-5, 1 PI., 1887. 
New species D. saltitans, C. formosus. 
60. Ibid. Observations sur les Chaetonotus et les Dasydytes. 
Journ. de Microg., 12, 2 parts, January, 1888. 
A translation of the preceding paper. 
*61. Tatem, T. G. New Species of Microscopic Animals. Quart. 
Journ. of Micr. Sci., N.S. 7, pp. 251-2, 1867. 
New species Chaetonotus longicaudatus. 
*62. Thompson, P. G. A new species of Dasydytes. Science 
Gossip, No. 319, 1891. 
New species D. bisetosus. 
*63. Yoigt, M. Bisher unbekannte Siisswasserorganismen. 
Zool. Anz., xxiv., No. 640, pp. 191-4, 1901. 

New species Chaetonotus serraticaadus, C. nodicaudus. 
*64. Ibid. Unbesehriebene ' Organ. Plon. Gewassern. Zool. 
Anz., xxv., No. 660, pp. 35-9, 1901. 

New species Ichthydium forcipatum, Chaetonotus- chuni, 
Dasydytes stylifer. 
*65. Ibid. Rot. u. Gast. d. Umgebung v. Plon. Zool. Anz., xxv., 
No. 692, pp. 673-81, 1902. 

He names nine species as new, but gives no descriptions 
or figures except of one. Eight of them had been de- 
scribed in earlier papers. The nine names are Ichthydium 
forcijxitum, Aspidonotus paradoxus (n. gen., n. sp.), Chae- 
tonotus linguaeformis, C. nodicaudus, C. serraticaudus, C. 
uncinus, C. succinctus, C. chuni, Dasydytes stylifer. He 
describes Aspidonotus and (p. 681) figures one scale. 



236 J. MURRAY ON GASTROTRICHA. 

*66. Ibid. Drei neue Ohaetonotus-Arten a. Plon. Gew'assern. 
Zool. Anz., xxv., No. 662, pp. 116-18, January, 1902. 
New species C. linguaeformis, C. succinctus, C. uncinus. 

*67. Ibid. Erne neue Gastrotrichenspecies (Chaetonotus arquatus) 
aus dem Schlossparkteiche zu Plon. Forschber. Biol. Stat. 
Plon., x., pp. 1-4, 1903. 

68. Ibid. Rotatorien u. Gastrotrichen d. TJmgebung von Plon. 
Ploner Forsch.-ber., xi., 180 pp., 1904. 

He records twenty-three species and describes nine as 
new, but these have been described in earlier papers. He 
renames the genus he had called Aspidonotus, making it 
Aspidiophorus, as he found that the former name was 
preoccupied. 

*69. Ibid. Nachtrag zur Gastrotrichen-Fauna Plons. Zool. 
Anz., xxxiv., No. 24/25, pp. 717-22, 1909. 

New species Chaetonotus ploenensis, C. simrothi, Dasy- 
dytes dubius, D. festinans, D. ornatus. 

70. Wagner, F. Der Organismus der Gastrotrichen. Biol. 
Centralb., 3, No. 7/8, 1893. 

71. Zelinka, C. Die Gastrotrichen. Zeit. f. iviss. Zool., 49, 
pp. 299-476, PI. 11-15, 1889. 

An important paper, the most careful and scientific 
that has appeared on the subject. He gives a good and 
full account of the anatomy, a good bibliography, and a 
good resume of all the systematic work on the group, 
quoting most of the authors' original descriptions. Some 
previously described species escaped his notice, as Ichthy- 
dium entzii Dad. Two new genera and four new species 
are described. The genus Gossea is framed to contain 
Gosse's Dasydytes antenniger, Lepidoderma for Dujardin's 
Chaetonotus squammatus, with C. rhomboides Stokes, 
Ichthydium ocellatum Metch., and C. concinnum Stokes. 
Lepidoderma is an unfortunate genus, as the type species 
(C. squammatus Duj.) is spiny and a true Chaetonotus. C. 
rhomboides Stokes is usually spiny, and /. ocellatum Metch. 
is not stated or figured by its discoverer to have scales. 

The new species are Chaetonotus similis, C. brevi- 
spinosus, C. Qiiacrochaetus, C. persetosus. 

72. Marcolongo, Ines. I Gastrotrichi del lago-stagno craterico 
di Astroni. Atti Ace. Sci. Fio. e Nat. Napoli, vol. 14. 



J. MURRAY ON GASTROTRICHA. 237 



Explanation of Plate 19. 

Scale and hair of : 
Fig. 1. G. macrochaetus Zel. (After Zelinka.) 



55 
?5 
55 
55 
?5 
55 
55 
55 
55 
55 

55 

55 
55 
55 
55 
55 
?> 
fl 
55 
55 
)5 
55 



9 



6'. hystrix Metsch. 

3. C. si?nilis Zel. (After Zelinka.) 

4. C. maximus Ehr. (After Zelinka.) 

5. G. persetosus Zel. (After Zelinka.) 

6. G. pusillus Dad. (After Daday.) 

7. C heterochaetus Dad. (After Daday.) 

8. C. schidtzei Metch. (After Zelinka.) 

9. G. larus Miill. (After Ludwig.) 
10. C. erinaceus Dad. (After Daday.) 

11 a. G. succinctus Voigt, one of the long bristles. (After 

Voigt.) 
116. C. succinctus Yoigt, scale from posterior part. (After 

Voigt.) 

12. G. hystrix Metsch. (After Zelinka.) 

13. C. nodicaudus Voigt. (After Voigt.) 

14. Aspidiophor us paradoxus Voigt. (After Voigt.) 

15. Lepidoderma ehngata Dad. (After Daday.) 

16. C. brevispinosus Zel. (After Zelinka.) 

17. C. arquatus Voigt. (After Voigt.) 

18. G. simrothi Voigt. (After Voigt.) 

19. G. zelinkai Grim. (After Griinspan.) 

20. C. uncinus Voigt. (After Voigt.) 

21. G. chuni Voigt. (After Voigt.) 

22. C. linyuaeformis Voigt. (After Voigt.) 



23. Ichthydium sp. (?). 

24. Lepidoderma loricata Stokes. (After Stokes.) 
25a. Dasydytes goniathrix Gosse. Drawn from nature. 
256. D. goniathrix Gosse. A single seta. 

26. C. entzii Dad. (?). Differs from Daday's in having the 
furca without hairs. 

27. Dasydytes bisetosus Thomp. Drawn from nature. 
28a. Gossea antennigera Gosse. Drawn from nature. 
286. G. antennigera Gosse. Scale and hair. 

? , 29. Lepidoderma, very small species. Drawn from life. 



238 J. MURRAY ON GASTROTRICHA. 

Fig. 30. Chaetonotus sp. (?). Scales as in C. larus (fig. 9), but 
rows more numerous. 
31. Chaetonotus sp. (?). With very distinct rhomboid scales. 
316. Chaetonotus sp. (?). Three of the scales. 

32. Setopus primus Griin. (After Griinspan.) 

33. Chaetura piscator sp. n. 

34. Chaetonotus sp. (?). All hairs long, widely spreading. 

35. Chaetonotus or Lepidoderma. Like the animal figured 
by Zelinka as L. ocellatam Met., but I saw no 
eyelike bodies. Metchnikoff did not describe his 
animal as scaly. 

,, 36. Scales of C. tenuis Griin. (After Griinspan.) 



Journ. Qvekett Microscopical Club, Ser. 2, Vol. XII., No. 73, November 1913. 



Ser. 2, Vol. XII., PI. 19. 




J. Murray, del. adnat. 



Gastrotricha. 



239 



NOTES 

ON A NEW METHOD OF MEASURING THE 
MAGNIFYING POWER OF A MICROSCOPE. 

By Edward M. Nelson, F.R.M.S. 

{Read June 2Wi, 1913.) 

Many microscopists, at one time or another, will have experienced 
some trouble about the determination of the combined magni- 
fying powers of their objectives and eyepieces. Some never 
measure them at all, and rely upon the manufacturer's catalogues 
for the results. This is not very satisfactory, for neither 
objectives nor eyepieces turn out to be at precisely their nominal 
foci ; and if both these should happen to be either in excess or 
deficit the actual magnifying power will differ considerably from 
that given in the catalogue. Therefore it will be better for every 
one to measure the magnifying powers of the lenses of their 
microscope. 

There are two well-known methods of doing this. The first, 
and perhaps the simplest, is to employ a photomicrographic 
camera to measure the magnified image of the stage micro- 
meter when projected on to the ground glass at a distance of ten 
inches. The second is to project the magnified image of the 
stage micrometer, by means of some sort of a camera lucida, on to 
a scale, distant ten inches as before. 

All this appears delightfully simple, but w^hen examined more 
carefully it is not really so. First, the photomicrographic-camera 
method requires a dark room, or the measurement must be made 
at night, and of course it is sure to happen that when the 
camera is most wanted it is not available. This is just what has 
occurred to me. My photomicrographic camera and stand, which 



240 E. M. NELSON ON A NEW METHOD OF MEASURING THE 

are large and heavy, are packed away ; it would take some 
hours to unpack them, clear out a room for their reception, 
bring them in and set them up, so I have to be content with 
some other means of measuring magnifying powers. 

The second method, viz. that of employing a camera lucida, 
also appears to be very simple, and so it is when a Powell No. 1 
stand is used, which has its optic axis ten inches from the table, 
when inclined horizontally ; a Beale's neutral tint fitting on the 
" capped" eyepieces answers perfectly some attention, however, 
is necessary to regulate the illumination, both in the tube and on 
the rule, otherwise the coincidences of the lines cannot be 
observed. But suppose a continental eyepiece is used, what 
then ? The Beale camera will not fit, and all the simplicity of 
one's arrangements and apparatus fails. If the microscope is 
not a Powell's No. 1, then it must be placed upon a box, and the 
distance of the rule adjusted by means of other boxes, books, 
etc. With a Continental microscope matters are no better. One 
has the simplicity of the Abbe camera, with its cleverly planned 
device for regulating the illumination of the stage micrometer 
and of the rule, but suppose the eyepiece is of the positive com- 
pensating type, what is to be done ? The camera will not fit 
and cannot be used. There are other cameras, both of the right- 
angled and of the oblique type ; some eyepieces they fit and 
others they do not. These difficulties are not imaginary, for 
I have experienced all of them at one time or another. The 
apparatus I now use is the old-fashioned Wollaston's camera, 
mounted on a table screw clamp. This can be used with every 
kind of eyepiece ; it is, however, troublesome to work with, and 
it requires some practice to obtain a coincidence of the scales 
how anybody can execute a drawing with such an apparatus is, 
to me, quite incomprehensible ! 

I have devised an entirely new method by which all these 
worrying little troubles may be avoided. First, it is necessary 
to determine the " constant " of the eyepiece with a given tube 
length. This is easily done, and when done it should be recorded, 
or better still engraved on the eyepiece tube. To find the 
" constant " of an eyepiece with a given tube length, first 
determine the combined magnifying power of that eyepiece on 
the given tube length with any objective, say one of medium 
power, sudh as a |-in. or J-in. or |%-in. focus. Secondly, measure 



MAGNIFYING POWER OF A MICROSCOPE. 241 

the exact diameter of the field by means of the stage micro- 
meter. The product of these two quantities is the constant of 
that eyepiece with the given tube length. 

Example : objective -in., eyepiece compensating x 8, tube 
length 170 mm., measured magnifying power 280 diams. : 
measured field 0-023 in. Product is 6'44, which is the constant 
of that eyepiece for 170-mm. tube. 

The power of any other objective with this eyepiece and tube 
length can be determined by merely measuring the diameter of its 
field by the stage micrometer ; for the magnifying power will ob- 
viously be the eyepiece constant divided by the diameter of the field. 

Thus, the problem of measuring the combined magnifying 
power is brought down to the bed-rock of simplicity. No camera, 
no regulation of illumination, no ten inches to measure ; in brief, 
nothing to do but to count the number of divisions of the stage 
micrometer in a diameter of the field and then divide this into 
the eyepiece constant. 

Example 1. With the same x8 compensating eyepiece and 

170-mm. tube a |--in. objective gave a diameter of field of 

6-44 
0*0165 in. The magnifying power therefore is r w = 390. 

Example 2. With the same x 8 compensating eyepiece and 

1 70-mm. tube a 1 J-in. objective gave a diameter of field of 0*185 in. 

6-44 

The magnifying power therefore is .... = 35. 

The determination of the constant is scarcely any more trouble 

than the measurement of the magnifying power of one objective, 

and when once found need not be determined again ; it would 

ndeed be most helpful if manufacturers would measure these 

constants and engrave them upon the tubes of their eyepieces. 

Obviously the diameter of the field can be measured while the 
microscope work in hand is being carried on, for it disturbs neither 
the microscope nor its adjustments. 

This method has been tested with thirty- three object glasses, 
ranging from a 3-in. to a yTrth of 1'4 IS". A., by fourteen different 
makers, and with various eyepieces, on three different microscopes 
with different tube lengths, and it has been found correct. 

My best thanks are due to Mr. Grundy for his kind assistance and 
notes. Further experience has shown that in determining the 
" constant " it is better to measure the magnifying power by 



242 E. M. NELSON ON A NEW METHOD OF MEASURING THE 

direct projection on to a scale, without the intervention of any 
camera lucida or drawing instrument ; the position of the 
Ramsden's disc, from which the 10-in. projection distance is 
measured, is easily found by means of a piece of ground glass. 
An excellent scale for the measurement of low powers is a 
Lufkin 3-in., No. 2111, price Is. 

[Practical members ma} 7 , by this time, be ready to ask, " What 
is the practical use of this system ? ' As a general answer it 
might be said that it shows how the materials for an important 
microscopical measuring tool can be easily determined. 

But another practical reason for my taking interest in our 
veteran member's paper is the hope that it will stimulate some 
of us to take an increased interest in microscopical measurements. 

I hardly need to impress on members the value of actually 
measuring objects, beyond offering a reminder, that measurements 
are the fundamental basis of microscopical science, and of every 
branch of science. Some would, perhaps, claim to put mathe- 
matics in this honourable position, but mathematics would be in 
a most sorry plight without measurements in various forms. 

Mr. Nelson, in a letter, says : " The combined magnifying 
power is wanted for drawings. Beale's method of exhibiting a 
drawing of the stage micrometer with the picture is quite the 
best, but it is adopted by only a few authors." And he mentions 
an instance of great trouble being caused by some drawings in 
books on microscopical subjects having the magnifications wrongly 
stated in the legend. 

It will have been noticed that Mr. Nelson has, hitherto, con- 
fined the use of the "eyepiece constant," for one eyepiece, to one 
definite tube length for one constant ; but used it for getting 
the total magnification with varying powers of objectives. 

Tests have, however, shown that the total magnification can be 
determined, by his method, for different tube lengths just in the 
same way as for different powers of objectives. Mr. Nelson 
himself says that " increase of tube length increases the power 
and, of course, diminishes the field, and is just the same as 
putting a higher-power objective on the nosepiece ; the constant 
of the eyepiece remains the same." In support of this statement, 
I give below r a few of the results of experiments made by Mr. 
Nelson not many days ago. 



MAGNIFYING POWER OF A MICROSCOPE. 



243 



Tests with Powell & Lealand's Low-angled ^in. Objective. 



Eyepiece. 


Tube length. 


Diameter of field. 


Magnifying power. 


Eyepiece constant. 


No. 1 


12 in. 
5 ., 


0-036 
0-0675 


103 
56 


3-708 
3-7N 


No. 2 


12 in. 

6 


0-031 
0-0615 


135 

7(> 


4-185 
4-305 


No. 4 


12 in. 

6 


0-0267 
0-052 


267 
135 


7-129 
7-02 



Other Tests with ^-in. Objective. 





Eyepiece constants. 


Eyepiece. 


Tube length, 8*75 in. 


Tube length, 6 - 7 in. 


A(E) 
Z 12 C 

W 1 
2 

K3 


613 

5-2 
3-69 
413 
5-64 


6-04 

51 

3-54 

4-10 

5-6 




Tube length, 14*6 in. 


Tube length, 5 -3 in. 


K3 


5-62 


5-64 


Magnifications . . 250 


94 



Notice how nearly alike the eyepiece constant is for each pair 
of tests when different tube lengths are used, but the same eye- 
piece and objective. The last pair are practically the same, 
although the tube lengths vary to an extraordinary extent. 
Mr. Nelson says that "they are all done with extreme accuracy 
by projection. In every case the Ramsden's disc was found and 
the screen placed ten inches from it." The magnifications were 
250 and 94 diameters. 

There is another easy way in which the information given by 
the " eyepiece constant " may be used for determining the total 
magnification for any tube length. Suppose, for example, the 
eyepiece constant has been obtained with a given objective, eye- 
piece, and tube length, a record being made ; then it is only 
necessary to work a very simple proportion sum to determine at 
any time the total approximate magnification with any tube 



244 E. M. NELSON ON MAGNIFYING POWER OF A MICROSCOPE 

length. All other conditions being the same, the total mag- 
nification will be proportional to the tube lengths used. 

Take the extraordinary difference of tube length shown by the 
figures given below : 

Tube length. Magnification. 

14-6 in. 250 

5-3 in. 94 

Then 

Magnifica- 
Magnification with long tube x short tube length 250 x 5-3 tion for 

short tube 
length. 

Magnifica- 
tion for 

Snort tube length. 5 # 3 ' long tube 

length. 

It is also worth mentioning that the diameter of the field may 
be measured in millimetres, instead of inches, if millimetres are 
used when determining the value of the eyepiece constant. And 
members will probably find this a great convenience. 

J. Grundy.] 



Long tube length 


14-6 


And 




Magnification with short tube x long tube length 


94 x 14-6 



Journ. Quekett Microscopical Club, Ser. 2, Vol. XII. , No. 73. November 1913. 



245 



PROCEEDINGS 

OF THE 

QUEKETT MICROSCOPICAL CLUB. 

At the meeting of the Club held on March 25th, 1913, the 
President, Prof. A. Dendy, D.Sc, F.R.S., in the chair, the 
minutes of the meeting held on February 25th were read and 
confirmed. 

Messrs. J. T. Cook, David Henry Shuckard and W. E. 
Ford-Fone were balloted for and duly elected members of the 
Club. 

The Hon. Secretary announced that Mr. G. T. Harris, of 
Sidmouth, a former member of the Club, had made a very 
handsome donation in the form of a type collection of Hydrozoa, 
numbering 72 preparations. These had been collected on the 
south-west and west coasts of England, and should prove 
very useful to any member making a systematic study of the 
group, especially as the slides are accompanied by a resume as 
a help in diagnosing the more difficult species. Mr. Harris 
also sent a paper which will be read at the next meeting, on 
"The Collection and Preservation of the Hydrozoa." 

A vote of thanks to Mr. Harris for his valuable donation 
was proposed by the President, and carried by acclamation. 

Mr. A. A. C. Eliot Merlin, F.R M.S., sent for exhibition five 
photomicrographs, taken at x 320, of diatoms from a slide 
prepared by the late C. Haughton Gill (see Journal R.M.S., 
1890, p. 435). They were of Epithemia turgida, Stauroneis 
phoenice7ite?'07i, Pinnularia major, under surface showing per- 
forations on ribbing partly filled with the mercurous sulphide, 
and two others. 

A paper by Messrs. Heron-Allen and Earland, "On some 
Foraminifera from the Southern Area of the North Sea, dredged 
by the Fisheries cruiser ' Huxley ,'" was read by Mr. Earland. 
Mr. Earland said that after the reading of the paper by Mr. 
Heron-Allen and himself, " On the Occurrence of Saccammina 



246 PROCEEDINGS OF THE 

sphaerica and Psammosphaeria fitsca," before the " Challenger " 
society in October of last year, Mr. J. 0. Borley, of the Fisheries 
Department of the Board of Agriculture, suggested that it would 
be interesting if they continued their investigations in the 
southern area of the North Sea with a view to determining the 
distribution of the two species in that area. This, after some 
hesitation, they agreed to do ; but with little expectation that 
any observations of interest would result, as Mr. Borley had 
already confirmed, from his personal experience, the generally 
held opinion that Foraminifera of all kinds were of extremely 
rare occurrence in these waters. The shallowness of the sea, 
and consequent disturbance due to wave and tidal action, were 
considered to be factors limiting the possibilities of Khizopodal 
distribution. Material was examined from six stations repre- 
senting two widely separated areas of the North Sea, three 
stations being far to the north-east of the Dogger Bank near the 
Great Fisher Bank, while the other three stations were in the 
belt of deep water which lies to the west of the Dogger, close in 
to the Northumberland coast. The depths ranged between 31 
and 45 fathoms. 

A number of photomicrographs were projected upon the screen, 
and briefly described by Mr. Earland. Nubecidaria lucifuga 
(Def ranee), a southern form, has an extended range as far as 
the English Channel. It is common at Bognor and Selsey, and 
a few specimens had been found near the Orkneys and in Moray 
Firth. Miliolina seminulum (Linne) occurs at every station in 
both areas. It is the dominant miliolid of the North Sea, and 
is of world-wide distribution. Of the two species especially 
searched for Psammosphaera fusca (Schulze) was found to occur 
at all stations except one in the inshore area. Saccammina 
sphaerica (Sars) does not occur in any of the outer, or Great 
Fisher Bank, collections, but does occur at two inshore stations. 
The specimens found were extremely small. The dominant 
arenaceous form was Eeophax scorpiurus (Montfort). The 
dominant Textularian was Verneuilina polystropha. It occurred 
in great numbers and variety at every station. The genus 
Lagena is abundantly represented in the inshore station dredg- 
ings, twenty-eight species being recorded, while at the outer 
stations only eight species were found. Truncatidina lobatula 
(W. and J.), Nonionina depressula (W. and J.), and Polystomella 



QUEKETT MICROSCOPICAL CLUB. 247 

striato-punctata (F. and M.) occur abundantly everywhere, and 
form the bulk of all the cleaned material. 

The President, in proposing a vote of thanks for the paper, 
said he much admired the photographs shown, which were the 
best of the kind he had seen. He would like to ask Mr. Ear- 
land, with regard to the criteria of specific characters, How 
could one tell one species from another, seeing that there is so 
much variation within the same species ? 

The vote of thanks was carried unanimously. 

In replying, Mr. Earland said he had to thank Mr. A. E. 
Smith for making the negatives, and Mr. Lovegrove for the 
lantern slides. Regarding specific differences, probably Prof. 
Dendy would have no difficulty in identifying sponges which he 
(Mr. Earland) would not be able to tell one from another. 
There are constant points always present which make it more 
or less easy to diagnose within certain limits. As regards specific 
features in Foraminifera, there are none such as we find between, 
say, a cat and a dog. Probably generic differences in Fora- 
minifera are about equal to specific differences in higher forms. 

Mr. D. Bryce gave a resume of a paper he had contributed 
on " Five New Species of Bdelloid Rotifers." Four of the new 
species belong to that important section of the Philodiniclae in 
which the food is formed into pellets after passing through the 
mastax, and are assigned to the genus Habrotrocha. The new 
species are IT. munda, H. torquata, U. spicida, and H. ligula. 
The fifth species, Callidina Bilfingeri, belongs to the more 
numerous section of the same family in which the food is not 
at any time agglutinated into pellets, and being oviparous, and 
possessed of three toes, is a member of the genus Callidina, as 
now restricted. 

The President said they were all much indebted to Mr. Bryce 
for bringing these interesting details before them. 

A vote of thanks to Mr. Brvce for his communication was 
carried unanimously. 



At the meeting of the Club held on April 22nd, 1913, the 
Vice-President, E. J. Spitta, L.R.C.P., M.R.C.S., in the chair, 
the minutes of the meeting held on March 25th were read and 
confirmed. 



248 PROCEEDINGS OF THE 

Messrs. F. J. Cheshire, Henry Edwards, and H. D. Rawson 
were balloted for and duly elected members of the Club. 

The List of Donations to the Club was read and the thanks of 
the members voted to the donors. 

Mr. C. D. Soar, F.R.M.S., read a note describing two new 
species of water-mites. These were Arrhenurus Scourfeldi sp. 
now and Acercus longitarsus sp. nov.. The first was taken by 
Mr. Scourfield in Cornwall, in fresh water, in the autumn of 
1912. It belongs to the sub-genus Megalurus, female unknown. 
The new species of Acercus is named from the unusually long 
tarsi found in the fourth pair of legs. Locality, South .Devon- 
shire, female unknown. Mr. Soar also said that Mr. Williamson, 
F.R.S.E., in working out the material on the genus Sperchon 
had found two species new to Britain, and two that have only 
been recorded for Ireland. These were Sperchon clupeifer Pier, 
sub-genus Hispidosperchon, from Oban and Norfolk Broads. 
Sperchon tenuabllis Koen, sub-genus Hispidosperchon, from 
Oban. Recorded by Halbertin Clare Island Survey for Ireland. 
Sperchon papillosus, Sig. Thor, sub-genus Squamosus, Oban, 
recorded by Halbert for Ireland ; and Sperchon Thienemanni, 
Koen, sub-genus Rugosa, from Derbyshire. Drawings of the 
two new species were exhibited. 

The Chairman said they were all deeply indebted to Mr. Soar 
for bringing these new species of Hydrachnidae before them, and 
they would be able to appreciate the value of the paper more 
when in print. The drawings in illustration of the species 
described were very tine indeed. 

The thanks of the meeting were unanimously voted to Mr. Soar 
for his paper. 

In the absence of the author, the Hon. Treasurer, Mr. F. J. 
Perks, read a paper on " The Collection and Preservation of the 
Hydroida," by Mr. G. T. Harris, of Sidmouth, a former member 
of the Club. The author said that the Hydroida are too well 
known as affording both beautiful and interesting objects to need 
any eulogy at his hands. Bearing in mind that this paper is 
written more for the help of the novice than as a communication 
offering original matter, the writer wished to safeguard himself 
from any charge of carelessness by warning the uninitiated that 
collecting, say, rotifers and collecting hydroids are two totally and 
very dissimilar things. 



QUEKETT MICROSCOPICAL CLUB. 249 

A hearty vote of thanks was given to Mr. Harris for his 
interesting paper, which was well illustrated by about twenty 
preparations from those which he had presented to the Club at 
the March meeting. The preparations were arranged, mostly 
with dark-ground illumination, under microscopes kindly lent by 
Messrs. H. F. Angus & Co. 

The Chairman, in moving a vote of thanks to Messrs. Angus, 
which was carried bv acclamation, said that in London members 
took for granted that there was never any difficulty in getting 
their optician friends to lend the Club any reasonable number of 
microscopes ; but, as he had found by recent experience, outside 
of London such a thing was practically an impossibility ; even in a 
large town the number of microscopes available was very small. 
By being reminded of this he hoped they would more fully appre- 
ciate their good fortune. 



At the meeting of the Club held on May 27th, 1913, the 
President, Prof. A. Dendy, D.Sc, F.R.S., in the chair, the 
minutes of the meeting held on May 22nd were read and con- 
firmed. 

Messrs. Stanley Hall and Reginald Hook were balloted for and 
duly elected members of the Club. 

The list of donations to the Club was read and the thanks of 
the members were voted to the donors. 

The President said that for many years past a number of 
pamphlets, etc., had been received by the Club, which, not being 
considered of sufficient value to bind, had bden allowed to 
accumulate and were stored in a room downstairs. These had 
long been a kind of white elephant to the Committee, who had at 
length decided to deal with them, and had appointed a sub-com- 
mittee for this purpose. These gentlemen had gone through 
them and had come to the conclusion that a large mass of this 
material must be disposed of, and the question arose as to how 
this was to be done, and it had been resolved to offer the bulk to 
some dealer in second-hand books, but first of all to offer them to 
the members of the Club. For this purpose, lists would be pre- 
pared and laid upon the table at the next Gossip meeting and 
again at the next Ordinary meeting, for members to inspect and 
to make offers for any which they might care to possess. The 

Journ. Q. M. C Series II. No. 73. 17 



260 PROCEEDINGS OF THE 

Librarian was empowered to receive such offers for them and to 
accept those which he deemed satisfactory. It was not possible 
to bring them up for inspection, as there was about a ton and 
a half of them. 

A visitor, Mr. J. Watson, exhibited multiple images formed by 
the cornea of the eye of a hive bee mounted dry. 

Mr. J. Watson said the slide was that of the eye of a honey 
bee prepared so as to show the portrait of the bee-keeper in every 
facet just as the bee would see it. He had been told it could be 
done with the eye of a beetle, but that the hairs on the eye of the 
bee made it a difficult matter to accomplish; but by mounting the 
object in the way he described, so that the hairs were free from 
pressure on the under side of the slide, he had succeeded in 
obtaining the desired result, and he had obtained a good photo- 
graph of it with half an hour's exposure. 

The President said that at a Society such as theirs it w r as 
needless to explain that this was not the view which the bee got, 
as no doubt in some way it saw a single image, but he just men- 
tioned this to prevent any mistake, as he thought he heard it 
stated that this was how the bee saw the bee-master. Multiple 
images such as were shown could be got in a variety of ways, and 
he remembered that exactly the same thing was done at one of 
the Royal Society's soirees with the epidermic cells of a plant. 
They were, however, much obliged to Mr. Watson for bringing 
and explaining his exhibit. 

Mr. E. Inwards had found that a small knob fitted near the 
hinge -joint of the stop-carrier of substage condensers was more 
convenient in working than having to feel on the right for the 
usual long projecting end, which is very often in close proximity 
to the iris-handle. 

Mr. T. A. O'Donohoe read a paper illustrated by a number of 
lantern photographs, at various degrees of magnification, of the 
" Minute Structure of Coscinodiscus asteromjrfialus and of the two 
species of Plenrosigma, P. angulatium and P. balticum. Mr. 
O'Donohoe then showed an interesting series of photographs, at 
various magnifications, of P. balticum, some showing fine, hair- 
like, bent fibrils breaking away from the valve. Others showed 
the outer membrane breaking up into fibrils, and sometimes 
isolated dots. 

Mr. W. E. Brown said that the fibrils shown by Mr. O'Donohoe 



QUEKETT MICROSCOPICAL CLUB. 251 

had been known to him for a long time, but lie had never 
regarded them as structure, but rather as salt which had 
crystallised out after mounting. All these fibrils consisted of 
rows of dots connected by bars, and there always seemed to him 
to be some difference between these and the general structure. 

Mr. E. Pitt exhibited and described the Cambridge, Minot and 
Spencer microtomes, and, after the adjournment of the meeting, 
gave a demonstration of ribbon section-cutting. 

A vote of thanks was accorded Mr. Pitt for his exhibition. 



At the meeting of the Club held on June 24th, 1913, the 
President, Prof. A. Dendy, D.Sc, F.R.S., in the chair, the 
minutes of the meeting held on May 27th were read and con- 
firmed. 

Messrs. Frank Deed, C. Tierney, D. L. Newmarch, E. L. 
Fen wick, and H. H. Dean were balloted for and duly elected 
members of the Club. 

The list of donations to the Club was read, and the thanks 
of the members voted to the donors. 

The Hon. Secretary read a note from Mr. E. M. Nelson 
describing Koristka's new loup. The writer said that in 1885 
he brought to the notice of the Club the then new Zeiss-Steinheil 
loups, which had just arrived from Jena. These lenses have been 
very popular, and have since been copied by every maker, both 
here and on the Continent. 

There is now a new form of loup with which the Club should be 
acquainted; it is the achromatic doublet of Koristka. The following 
are the measured particulars (not taken from a catalogue) : 

Doublet, power 10, field 1| cm., working distance 2 cm. 

Top lens alone, ,, 5|, ,, 2 ,, 4 

Bottom lens alone, ,, 3|, 4 ,, ,, 5 

The defining pow r er of this loup is excellent, and prolonged 
work with it seems easier than with a Steinheil ; somehow or 
other work with a Steinheil is tiring to the eye. The price of 
this fine lens, in a wooden box, is only 12s., but although the 
price is so low, the quality of workmanship is particularly high. 
Among cheap loups we so often find that the lenses are im- 
perfectly polished, the threads of the screws badly cut, so that 
they do not engage readily, and the quality of materials used 



252 PROCEEDINGS OF THE 

inferior. But this new loup exhibits none of these defects, and 
Koristka is to be congratulated on having brought out at a low- 
figure a loup which compares favourably in the quality of its 
finish with the most expensive grades of work in this line. This 
high standard of workmanship extends also to Koristka's 
objectives, eye-pieces and other apparatus. 

Mr. A. A. C. Eliot Merlin, F.R.M.S., sent a note on " Secondary 

Hairs on Foot of a Ceylon Spider." The main hairs on the foot 

of a very large species of Ceylon spider, the name of which is 

unknown, have proved to be densely covered with small short 

spines or hairs so transparent as to be observable with difficulty 

even by means of an oil-immersion objective. The specimen 

examined was obtained and mounted in balsam by the late 

Staniforth Green, who was for many years resident at Colombo. 

When the main hairs are viewed with a dry lens, of moderately 

large aperture they plainly exhibit a regular clotted structure, 

this being composed of the ring root sockets of the secondary 

spines, which are themselves so transparent in the balsam mount 

as to require great aperture to define properly. It is suggested, 

however, that hairs from this, or similar, large species of spider 

might be mounted in glycerine jelly and might then exhibit the 

spines more easily. The preparation in which the spines have 

been noted happens to be, like most entomological mounts 

intended for examination under low or medium powers, provided 

with a cover-glass of considerable thickness, while the foot itself 

is large and by no means flat. Under these conditions an 

ordinary oil-immersion objective could not be employed, but 

fortunately a Powell one-twelfth achromatic, of measured N.A. 

1*27, obtained some fifteen years ago, possesses quite abnormal 

working distance compared with recent productions of similar, or 

slightly greater, aperture, and is to oil-immersion lenses what 

the new one-sixth moderate aperture objectives of great working 

distance are to dry systems. The lens in question has on several 

occasions proved invaluable for the examination of minute 

structure in ordinarily mounted entomological specimens. A 

photomicrograph at x 60 accompanied the paper for identification 

purpose, and was exhibited. 

Mr. Nelson sent for exhibition a section of Green Trap, basic 
igneous rock, a crystalline aggregation of serpentine. This, he 
wrote, might easily be mistaken for a piece of fossil nummulite, or 



QUEKETT MICROSCOPICAL CLUB. 253 

wood. Xt is probable that the fossil known as Eozoon cauadense, 
from the Laurentian serpentine, is of a similar nature. 

Mr. H. Sidebottom contributed a valuable paper on "The 
Lagenae of the South- West Pacific." Mr. A. Earland, F.R.M.S., 
in introducing this paper, said it was a very lengthy and valuable 
one, and the Club would be proud to include it in the Journal. 
It is Part 2 of a paper published in the April 1912 issue of 
the Journal. By the kindness of Mr. H. F. Angus, who arranged 
an exhibition frame for the drawings, he was able to exhibit 
some of Mr. Sidebottom s beautiful drawings. The majority of 
the stations from which the specimens dealt with were derived 
(if not all) lie within the region of the South Pacific known to 
oceanographers as the " Aldrich Deep." This area lies to the 
east of New Zealand, between 15 and 47, and covers about 
613,000 square miles. Three soundings exceeding 5,000 
fathoms have been recorded in this area by Commander Balfour 
in H.M.S. "Penguin" in 1895. The deepest sounding yet 
made, however, is one in the "Challenger" Deep, near Guam, 
in the Ladrone Islands. This is 5,269 fathoms, nearly six miles. 
The Aldrich Deep has the second deepest record, 5,155 fathoms. 
None of the material discussed in this paper comes from the 
deepest parts of the area. The depths given by Mr. Sidebottom 
range between 328 fathoms and 4,278 fathoms, but the majority 
are under 2,000 fathoms. No details are given of the nature 
of the material from which the specimens were derived, and 
possibly the information was not in the author's possession, as 
the majority, at any rate, of the specimens had been picked out 
by Mr. Thornhill prior to his death, when the type slides passed 
into the hands of Mr. Sidebottom for classification and description. 
It may, however, be fairly surmised that, owing to the distance 
of the area from any land, none of the samples would be terri- 
genous deposits, but would be true oceanic deposits. Globigerina 
and Pteropod oozes in the lesser depths, passing into pure 
Globigerina ooze, and, beyond the 2,000-fathom line, into Red 
Clay. The presence of a varied and rich fauna of Lagenaa in 
the deep water of the South Pacific has been recorded by the 
" Challenger" Some of the stations of that ship lie within the 
same area as the " Penguin " material worked by Mr. Sidebottom, 
but the " Challenger " material was either very poor in specimens 
compared with the "Penguin" or it was very incompletely 



254 PROCEEDINGS OF THE 

worked out. The genus Lagena, while of world-wide distribution 
and occurring at all depths, presents some rather curious 
anomalies as regards its occurrence in any abundance. It 
would probably be almost impossible to make a dredging or a 
shore gathering in any part of the world without finding the 
genus represented in the material. But, Mr. Earland said, 
from practical experience, both of deep and shallow water 
dredging and of shore collecting, he knew that in one sample 
the genus may be extremely rare, while in another of similar 
material taken a few miles away, under similar conditions of 
depth, the genus may be abundant and varied. The reason for 
such a difference is obscure, but is possibly based on the pro- 
portion of mud in the deposit. Legena as a genus is a lover of 
still and muddy bottoms. Globigerina oozes are, as a general 
rule, singularly poor in Lagenae : hence the greater wonder at 
the richness of the fauna in these " Penguin " oozes. Mr. 
Sidebottorn states that the late Mr. Thornhill had picked out 
over 12,000 specimens, and had commenced to arrange them on 
a scheme which he had devised but did not live to carry out. 
Personally, Mr. Earland said, he regretted that Mr. Sidebottom 
had not found time or opportunity to use the unique material 
which came into his possession at Mr. Thornhill's death, as a 
centre around which to build up a complete monograph of this 
beautiful genus. Perhaps he may yet find himself able to deal 
with this task. But, in any case, it is a matter for congratula- 
tion that Mr. Thornhill's work did not perish and disappear 
unrecognised on his death, as so often happens when a worker 
dies, but that his material has fallen into the hands of Mr. 
Sidebottom, whose beautiful drawings will make it accessible to 
all interested in the group. 

One of the most noticeable features of this group is the very 
large proportion of decorated forms. Many of the recognised 
species are very hard to identify on account of the almost in- 
finite variety and variation of the minute spines and markings 
which characterise them. The object of such markings seems 
to be quite beyond speculation. They are quite invisible to the 
naked eye, and, unlike the markings of diatoms, do not appear 
to have any physiological significance. Mr. Earland thought 
the Club was to be congratulated on obtaining two such notable 
papers for publication in its Journal, 



QUEKETT MICROSCOPICAL CLUB. 255 

The President said that he was afraid he was not able to 
throw any light on the significance of the markings and char- 
acters of the kind Mr. Earland had mentioned. He thought 
they were quite inexplicable at present. It must be admitted 
that a great number of specific characters are not due to adapta- 
tions, and one may go further and ask how far the origin of 
species is affected by natural selection. What proportion of 
specific characters are adaptations at all ? How often can one 
say that any character is really adaptive ? He would like the 
opinion of some of the Club workers. Would Mr. Rousselet, 
for instance, say that all the specific characters of rotifers were 
adaptations ? He would not say an organism w r as not adapted 
to its environment, but he would say that many organisms 
exhibit a whole host of characters not due to environment. 
They could not explain everything as due to natural selection. 
Darwin laid great stress on " The Origin of Species by Means 
of Natural Selection," and thought that specific characters came 
first, and then natural selection came in and weeded out any 
not suited to the environment. 

Mr. C. F. Rousselet thought it was impossible to determine 
what characters were really adaptive in the Rotifera. 

Mr. D. Bryce said natural selection did not apply to his 
Bdelloids, as they were all females. It was a real case of sur- 
vival of the fittest. Occasionally a specific character must be 
an absolute hindrance, and, in the case of long spines, must 
sometimes be positively dangerous. 

The President said it was very difficult to put oneself in the 
position of, for instance, a sponge. But take the case, say, of a 
small protuberance on a spicule, which spicule is quite sur- 
rounded and embedded in the general protoplasmic mass of the 
animal, and then assume another similar spicule which is without 
such protuberance. It is not possible to conceive that either 
the presence or absence of such a minute speck of silica could 
be of any use to the individual, and yet such a difference is often 
absolutely characteristic of a species. We have had instanced 
this evening elaborate decoration and markings on Foraminifera. 
These animals certainly cannot appreciate them visually, as they 
have no organs of vision ; and, again, in life the markings would 
be concealed under the usual gelatinous mass of exterior proto- 
plasm. The markings are so minute that it is quite impossible 



256 Proceedings of the 

that the organisms could be cognisant of their existence in any 
way. The markings are of such a nature as to be quite without 
use to the organism, and we may take it that the possession of 
one particular pattern is of just as much, or little, use to the 
organism as the possession of any other pattern. Have we any 
right to say that any one of the patterns is an adaptation ? 

Mr. A. E. Hilton cited the case of the Mycetozoa, where the 
specific nomenclature is based on minute markings on the capil- 
litium. These markings are really the waste products of the 
protoplasm which is purifying itself in spore-formation. It is 
quite certain that the cause of the different markings must be 
in the protoplasm itself. The protoplasm of different species 
makes deposits in different shapes, and these must be largely 
dependent on the condition of the air, as regards temperature 
and moisture, at the times of spore-formation. The real seat 
of the difference lies in the protoplasm itself. 

Mr. W. It. Traviss exhibited and described a simple apparatus, 
for use in pond-hunting, for collecting water from depths which 
cannot be reached with the usual dipping-tube and stick. It 
consisted of a light metal cylinder closed at one end. At the 
other a light frame is fixed in a sort of handle-shape. This 
frame serves as support to a stout metal rod, which is fastened 
at the other end centrally to the bottom of the cylinder. On 
the rod slides loosely, first, an easily fitting cap to the cylinder, 
and, next, several lead discs. A string is attached to the bottom 
of the cylinder actually to an eye formed by bending the end 
of the central rod which is projecting outside. Another string 
is attached to the opposite end of the rod. In use the weight 
of the lead discs is so adjusted that they will take the cylinder 
down to the bottom, upside down and full of air, the contrivance 
being lowered by the string attached to the bottom, the other 
string hanging slack. On reaching the bottom, or, if desired, 
some particular depth which could be marked on the string, the 
second string is gently pulled, bringing the mouth of the cylinder 
away from the bottom, and permitting some of the contained 
air to escape. Two or three tugs at the string will allow all the 
air to rush out, and at the same time fill the cylinder with 
bottom-water. It will now be right side up, and the lead weights 
which carried it down will keep the loosely fitting lid in position 
as the apparatus is drawn up by the top string. Practically no 



QUEKETT MICROSCOPICAL CLUB. 257 

exchange of water takes place. Mr. Traviss also exhibited a 
very convenient and portable form of siphon-strainer. 

Several members testified as to the efficiency of Mr. Traviss's 
apparatus, which he used at the last excursion of the Club 
(June 21st). 

A paper " On a New Method of Measuring the Magnifying- 
power of a Microscope," communicated by Mr. E. M. Nelson, 
F.R.M.S., was read by Mr. J. Grundy. 

After reading Mr. Nelson's paper, Mr, Grundy offered a few 
remarks of his own. 

Mr. Grundy exhibited a modification of the photomicrographic 
camera projection method. A light cardboard tube of about 
24 in. diameter and about 12 in. in length fits loosely over the 
eye-piece ; the other end is supported by a clamp-stand. (The 
microscope may be in any position; inclined is most convenient.) 
At a distance of about 10 in. from the lower end a circle of fine 
ground-glass is fitted. This is carried in a " draw-tube," per- 
mitting correction for the position of the Ramsden disc for 
various eye-pieces or for different tube-lengths. If a micrometer 
is placed on the stage the projected image may be observed on 
the ground-glass, and the divisions gauged with dividers, and 
compared directly with an ordinary rule. Mr. Grundy also 
exhibited microscopes fitted with Beale's neutral-tint camera- 
lucida, Ashe's modification of Beale's form, and a Wollaston 
model. 

The President said they were much indebted to Mr. Nelson 
for his paper, and to Mr. Grundy for reading it. He had himself 
very often to make microscopical measurements, and though no 
doubt the method described was very good in theory he did not 
know how it would work out in practice as compared with the 
very simple method which he was accustomed to adopt namely, 
by drawing the object with a Beale's camera, and then in the 
same way drawing the micrometer scale when placed on the 
stage in place of the object. By applying these to one another 
he could measure a thing in a very short time, and did not see 
how he could possibly go wrong in so doing, although there might 
be a slight distortion caused by the eye-piece. 

A cordial vote of thanks was accorded to Mr. Nelson for his 
useful paper, and to Mr. Grundy for the interesting way in 
which he had brought the paper before the Club. 

Journ. Q. M. G, Series II. No. 73. 18 



258 



OBITUARY NOTICE. 

THE RIGHT HON. SIR FORD NORTH, 
P.C., F.R.S., F.R.M.S. 

Bom January \th, 1830; died October 12th, 1913. 

We regret to record the death of Sir Ford North, one of our well- 
known members. He died at his estate in Morayshire, in his eighty- 
fourth year. He was the son of a solicitor, and became a barrister 
practising in the Chancery Courts (1856). He was made a Q.C. 
in 1877, and afterwards a judge, at first in the Queen's Bench 
division (1881), and then in the Court of Chancery (1883), He 
was a Fellow 7 of the Royal Society, and a well-known entomologist. 
He was elected a member of the Q.M.C. in June 1894, and in the 
same year F.R.M.S. ; hewasamember of our Committee in February 
1899, and was one of our Vice-Presidents from February 1901. 
His unassuming and cordial manner and the interest he displayed 
in the objects exhibited by members produced a feeling of friend- 
ship towards him in all those who had the pleasure of meeting 
him, while his patience and experience in directing a meeting 
when he occupied the chair, as was frequently the case, made him 
a most valuable member of the Club, and one whose loss we all 
greatly regret. 



259 



THE PRESIDENT'S ADDRESS. 

ORGANISMS AND ORIGINS. 

By Prof. Arthur Dendy, D.Sc., F.R.S. 

(Delivered February 2ith, 1914.) 

I have in my library a copy of a posthumous edition, 
published in 1732, of a remarkable work by John Ray, entitled 
" Three Physico-Theological Discourses, concerning I. The Primi- 
tive Chaos, and Creation of the World. II. The General Deluge, 
its Causes and Effects. III. The Dissolution of the World, and 
Future Conflagration." The second of these discourses contains a 
very long discussion on the origin of fossils, which begins as 
follows : " Another supposed Effect of the Flood, was a bringing 
up out of the Sea, and scattering all the Earth over, an innumer- 
able Multitude of Shells and Shell-Fish ; there being of these 
Shell-like Bodies, not only on lower Grounds and Hillocks, but 
upon the highest Mountains, the Apennine and Alps themselves. 
A supposed Effect, I say, because it is not yet agreed among the 
Learned, whether these Bodies, formerly called petrified Shells, but 
now-a-days passing by the Name of formed Stones, be original 
Productions of Nature, formed in imitation of the Shells of 
Fishes ; or the real Shells themselves, either remaining still 
entire and uncorrupt, or petrified and turned into Stone, or, at 
least, Stones cast in some Animal Mold. Both Parts have strong 
Arguments and Patrons. I shall not balance Authorities, but 
only consider and weigh Arguments." 

In the end Ray pronounces in favour of the view that the 
fossils are real shells and not mere sports of nature, but he adopts 
a most singular hypothesis as to how they found their way into 
their present situations. It is only fair to add that this hypothesis 
did not originate with him, but was the offspring of the fertile 
brain of his " learned and ingenious Friend, Mr. Edward Lhwyd."* 

* 1 am indebted to rny friend, Mr. A. W. Sheppard, the Editor of this 
Journal, for the information that Mr. Edward Lhwyd, M.A., F.R.S. , was 
keeper of the Ashmolean Museum from 1690 to 1709, and published a 
catalogue of fossils in 1699. 

Journ. Q. M. C , Series II. No 74. 19 



260 the president's address. 

Mr. Lhwyd appears to have been much impressed by the 
alleged fact that marine shells are sometimes generated in the 
bodies of men and other animals, though at the present day it is 
difficult enough to understand how such statements could ever 
have gained credence. He observes : " For to me it appears a far 
less Wonder, that Shells and other Marine Bodies should be pro- 
duc'd in the Bowels of the Earth, than their Production in the 
Bodies of Men or Animals at Land, And that they have been 
so found, is sufficiently attested, both by Ancient and Modern 
Authors, of a Credit and Character beyond all Exception." 
Obviously the universal deluge could hardly be held responsible 
for the occurrence of marine shells in human bodies, and there- 
fore why hold it responsible for the occurrence of similar things 
in the bowels of the earth % 

The ingenious Mr. Lhwyd proceeds as follows : " I therefore 
humbly offer to your Consideration, some Conjectures I have of 
late Years entertain'd concerning the Causes, Origine, and Use 
of these surprising Phenomena. I have, in short, imagin'd they 
might be partly owing to Fish Spawn received into the Chinks 
and other Meatus' s of the Earth in the Water of the Deluge, and 
so be deriv'd (as the Water could make way) amongst the 
Shelves or Layers of Stone, Earth, &c. and have farther thought 
it worth our Enquiry, whether the Exhalations which are raised 
out of the Sea, and falling down in Rains, Fogs, &c. do water 
the Earth to the Depth here required, may not from the 
Seminium, or Spawn of Marine Animals, be so far impregnated 
with, as to the naked E}^e invisible, animalcida, (and also witli 
separate or distinct Parts of them) as to produce these Marine 
Bodies, which have so much excited our Admiration, and indeed 
baffled our Reasoning, throughout the Globe of the Earth. I 
imagin'd farther, that the like Origine might be ascribe! to the 
Mineral Leaves and Branches, seeing we find that they are for 
the most part the Leaves of Ferns, and other Capillaries ; and of 
Mosses and such like Plants, as are called less perfect ; whose 
Seeds may be easily allow'd to be wash'd down by the Rain into 
the Depth here required." 

You will note that the Deluge has not completely disappeared 
from the hypothesis after all, but we may gather from what follows 
that it has crept in rather by force of habit, and that the author 
really relies principally upon the clouds and rain for conveying 



THE PRESIDENT'S ADDRESS. 261 

the " Seininium " into the crevices of the rocks where it is 
supposed to develop. Indeed, he accounts in this manner for the 
fact that so many of the fossil shells found in Great Britain 
belong to species not found in the adjacent seas. The " Seininium" 
has been brought from distant regions in the rain-clouds. 

In order to make his argument more convincing, Mr. Lhwyd, 
who is quite aware of some of its weakest paints, adopts the 
well-known method of answering possible critics in advance. 
" First" he says, "It will be questioned whether the supposed 
Seminium can penetrate the Pores of Stones." To this he replies 
" That it's manifest from Experience, upon which all solid 
Philosophy must be grounded, that the Spawn of Animals may 
insinuate itself into the Mass of Stone. And this plainly appears 
from Live Toads, found sometimes in the middle of Stones at 
Land, and those Shell-fish called Pholacles at Sea." In other 
words, facts are facts, and there is no getting away from 
them. " Secondly, 'It will scarce seem credible' that such Bodies, 
having no life, should grow, especia'ly when confined in so 
seemingly unnatural a Place as the Earth, &c." The answer 
to this is again supplied by the voice of authority, supplemented 
by an original observation on the part of the author which in- 
dicates clearly enough the amount of reliance that is to be placed 
upon his conclusions. " That's not so great a Wonder," he says, 
" as that Shells should be sometimes generated, and even grow, 
tho' they contain no Animals, within humane Bodies ; and within 
the Mass of those thick Shells of our large Tenby Oysters, 
which I formerly mentioned to you, as first shown me by Mr. 
William Cole of Bristol, and have since observ'd myself. For 
we must grant, that the Earth, even in any Part of the Inland 
Country, is much fitter for their Reception and Augmentation 
than humane Bodies ; especially, if we reflect, that when the 
Spat or Seminium here suppos'd meets with saline Moisture 
in the earth, living Animals are sometimes produced, as is before 
attested." And so on to ninthly and lastly. 

Evidently, in the year 1698, when this was written, the 
problem of how the apple got into the dumpling had not 
yet been solved by the philosophers. It is a little surprising, 
however, that such views should have been accepted by so 
experienced an observer as John Bay, who has been called 
the Father of modern zoological science. Nevertheless, he 



262 the president's address. 

quotes them at length, and adds : " For my part (if my Opinion 
be considerable) I think that my learned Friend hath sufficiently 
proved that these Fossil-shells were not brought in by the 
universal Deluge. He hath made it also highly probable, that 
they might be originally formed in the Places where they are 
now found by a spermatick Principle, in like manner as he 
supposes. Why do I say probable ? It is necessary that at least 
those, which are found in the Viscera and Glands of Animals, be 
thus formed ; and if these, why not those found in the Earth ? 
I shall say no more, but that those who are not satisfied with 
his Proofs, I wish they would but answer them." Thus even 
Kay, who was turned out of his Fellowship at Cambridge because 
he refused to make a declaration with regard to the Solemn 
League and Covenant demanded by the authorities, allowed 
himself to be completely enslaved by his own credulity with 
regard to unverified and, indeed, absurd statements as to the 
occurrence of marine shells in the bodies of land animals ! 

I suppose that Mr. Lhwyd's quaint hypothesis was almost the 
last of the many curious attempts that were made to explain 
the existence of fossils before our modern views on the subject 
came to be generally accepted. It affords an interesting illustra- 
tion of the power of uncriticised authority to lead people astray. 
Unfortunately, however, we cannot do without authority in science. 
No man has either time or opportunity to prove all things for 
himself. Progress is rendered possible only by the accumulation 
of the labours of many workers, each relying upon his fellows. 
The only safeguard against error is the free exercise of our 
critical faculty and the due restraint of our natural credulity 
the original sin of the scientific man. 

Let us turn now to another hypothesis. In 1875 Prof. Huxley, 
in one of his extraordinarily stimulating essays,* discussed the 
relation which exists between the composition of the earth's 
crust and the organisms by which it has been populated. He 
points out that the great Swedish naturalist Linmeus, who was 
born in 1707, only two years after the death of Kay, had already 
enunciated the dictum that "fossils are not the children, but the 
parents of the rocks " in other words, that rocks originate from 

* "On Some of the Results of the Expedition cf H.M.S. Challenger" 

1875]. Collected Essays, vol. viii. 



THE PRESIDENT'S ADDRESS. 263 

animals and not animals from rocks (" sic lapides ab animalibus, 
nee vice versa "). 

.After discussing the character of the various deposits which 
form the floor of the ocean, Prof. Huxley remarks : " If the 
Challenger hypothesis, that the red clay is the residue left by 
dissolved Foraminiferous skeletons, is correct, then all these 
deposits alike would be directly, or indirectly, the product of 
living organisms. But just as a siliceous deposit may be 
metamorphosed into opal or quartzite, and chalk into marble, 
so known metamorphic agencies may metamorphose clay into 
schist, clay-slate, slate, gneiss, or even granite. And thus, 
by the agency of the lowest and simplest of organisms, our 
imaginary globe might be covered with strata, of all the chief 
kinds of rock of which the known crust of the earth is composed, 
of indefinite thickness and extent. . . . 

" Accepting it provisionally, we arrive at the remarkable result 
that all the chief known constituents of the crust of the earth 
may have formed part of living bodies ; that they may be the 
; ash' of protoplasm/' 

The view that the red clay which forms the floor of the ocean 
at very great depths, and extends over an area of about fifty 
million square miles, is derived from the decay of the skeletons 
of Foraminifera from which the lime has been dissolved out, 
has not been substantiated by later investigations. According 
to Sir John Murray, the greatest authority on the subject, 
it has been formed chiefly by the disintegration of pumice and 
other volcanic ejecta. 

It thus appears that the " ash of protoplasm '' does not play 
nearly such an important part in the formation of the earth's 
crust as that suggested conditionally by Huxley. 

My indefatigable friend, Mr. Kirkpatrick, however, has for 
some time been raking in all sorts of ashes for evidence of their 
origin, and has come to the conclusion that even in the most 
unlikely situations traces of simple organisms may still be 
found.* He has, I fear, as yet met with but little success in 
convincing his scientific colleagues of the correctness of his 
observations, but his results are certainly in close agreement 
with the conclusions arrived at by Linnaeus and, provisionally, 
by Huxley. If these conclusions were correct we should have 
-* Vide The Niimmulosphere, by K. Kirkpatrick. London, 1913. 



264 the president's address. 

to conceive of the solid crust of the earth as the result of a 
constant interchange of matter between the living and the 
dead, accompanied by physical and chemical processes of endless 
complexity. We might even think of it as a huge composite 
organism, alive only at the surface, but built up on the waste 
products of its own collective metabolism, like a world-embracing 
coral reef. I fear, however, that such a conception would be 
more picturesque than accurate. 

Even if we accepted such a hypothesis we should, of course, 
have to remember that such a state of affairs could only have 
arisen through a slow and gradual process of evolution. 
Whether this process occupied a hundred million or a thousand 
million years would be a matter of comparatively small import- 
ance. It would be enough for our present purposes to recognise 
that it must have had a beginning at some extremely remote 
period of geological time, when the crust of the earth could not 
by any possibility have been composed of the detritus of living 
things. 

It is generally admitted that there are only two possibilities 
with regard to the origin of terrestrial organisms. Either thev 
must have been imported from some other planet in the form 
of germs, or they must have developed on the earth's surface 
from inorganic materials that formed part of the earth itself. 
Either event could only have taken place after the earth had 
cooled sufficiently to permit of the existence of those peculiarly 
unstable colloidal compounds of which living bodies are composed. 

The first hypothesis has, as you are aware, received the sup- 
port of no less eminent a man of science than the late Lord Kelvin, 
who believed it possible that the germs of living organisms 
might have been brought to the earth by meteorites. The chief 
objection to this view appears to be the difficulty of believing 
that any organism could withstand the heat generated by the 
friction of the meteorite with the earth's atmosphere. 

A modification of the same hypothesis, sometimes known as 
the Theory of Panspermia, is maintained by Svante Arrhenius 
and others. According to this theory, numerous living germs of 
extremely minute size occur scattered through space, derived 
from various planets upon which life is supposed to exist, 
though at present we have no proof whatever that life does 
exist upon any pi met except the earth itself. The nature of 



THE PRESIDENT'S ADDRESS. 265 

these invisible germs is enigmatical in the highest degree. They 
are supposed to be propelled through space by the pressure of 
the radiant energy streaming from the sun and it has indeed 
been demonstrated that very minute particles can be propelled in 
this way by rays of light. It has been objected to this view 
that no organisms could withstand the intense cold of inter- 
planetary space, but we know that living organisms withstand 
low temperatures much better than they withstand high ones, 
and there appears to be no known minimum at which all life 
is necessarily destroyed. A more serious objection is to be found 
in what is known of the fatal effects of ultra-violet light rays 
upon micro-organisms. At the surface of the earth such 
organisms are to a large extent screened from the effects of 
these rays by the earth's atmosphere, but this would not be the 
case in interplanetary space. 

Even if we were able to prove that living organisms first 
reached the earth from some other planet, however, it would 
not help us in the least to understand how they first originated. 
Such a hypothesis can only serve to remove the scene of action 
from the earth to some unknown sphere where the investigation 
of the problem is altogether beyond our reach. We may just 
as well assume at once that the first terrestrial organisms were 
generated in situ upon the earth itself and endeavour to find out 
how such generation may have occurred. 

This brings us to our second alternative, which we may speak 
of as the hypothesis of spontaneous generation, or, if we prefer 
Huxley's term, abiogenesis. The discussion of this question has 
unfortunately been greatly prejudiced by the hasty conclusions 
of various observers who from time to time have announced that 
they have actually witnessed the production of living organisms 
from not-living matter, a claim which has been repeated at 
intervals ever since people began to speculate on such subjects, 
but which no one has yet succeeded in substantiating. I shall 
refer presently to the latest efforts in this direction, but in the 
meantime we must carefully bear in mind that the sudden 
appearance of recognisable organisms where none previously 
existed, and in situations to which no living things can have 
gained access, is a very different thing from the gradual evolution 
of living matter from inorganic substances by slow and imper- 
ceptible steps, which are at first purely chemical and physical in 



266 the president's address. 

nature but gradually assume a character which distinguishes 
them more or less from ordinary physical and chemical processes 
and perhaps justifies us in speaking of them as vital. 

That there should be perfect continuity between not-living and 
living matter on the one hand, and between physico-chemical and 
vital processes on the other, is clearly demanded by the doctrine 
of evolution. Moreover we know that, at the present day, 
inorganic matter is constantly being converted into living proto- 
plasm, though only by the peculiar organising activities of 
living bodies. All organisms assimilate materials derived from 
their environment in order to build up their own bodies, and it 
is largely this power of assimilation that distinguishes them from 
bodies that are not alive. Daring life the organism conquers its 
environment and appropriates such portions of it as it requires. 
Death is the conquest of the organism by the environment, 
accompanied by re-annexation on the part of the inorganic world 
of all that the organism had appropriated during its lifetime. 

The chemist has no difficulty in analysing the complex col- 
loidal constituents of dead organisms into a descending series 
of less and less complex substances, ending with the so-called 
elements themselves. He has also, to a very great extent, accom- 
plished the reverse process, and has already carried his constructive 
operations as far as the synthesis of polypeptides, from which 
point to the proteids themselves is but another step. He has no 
right to assume, however, that when he has actually taken this 
step and, further, mixed his proteids with the other substances 
known to occur in living protoplasm, he will have produced 
anything that is actually endowed with life. We may even say, 
without much exaggeration, that the chemist, as such, has no 
knowledge of protoplasm at all, for it is impossible to analyse 
protoplasm while it is alive, and as soon as you kill it it ceases 
to be protoplasm. 

Even the simplest living things known to us behave in a 
manner which cannot, at any rate in the present state of our 
knowledge, be explained entirely in terms of chemistry and 
physics. The living organism itself plays the part of the chemist 
and the physicist, and we cannot explain the chemist or physicist 
in terms of the chemical and physical operations which he per- 
forms in his laboratory. Out of a multitude of possibilities the 
living organism selects those materials and those modes of action 



THE PRESIDENTS ADDRESS. 267 

which are consonant with its requirements as a living organism, 
and its power of meeting emergencies as they arise is the 
measure of its power to survive. Moreover, it is able to profit 
by experience and to learn how best to overcome the difficulties 
presented by its environment. This being so, we are justified in 
maintaining that even the simplest living thing is endowed with 
a certain degree of intelligence, for intelligence is nothing but 
the power of learning by experience how to perform purposive 
acts. 

We are not obliged, however, to suppose that the property 
which distinguishes the living from the not-living intelligence, 
vitality, or whatever we choose to term it came into existence 
suddenly. It is more in accord w r ith our experience in other 
directions to believe that it arose by imperceptible degrees, 
pari passu with the evolution of organic from inorganic matter. 
This, however, must not be taken to imply that there is no 
essential difference between living and not-living bodies, either in 
structure or behaviour. We might with equal justice say that, 
because water is a compound of oxygen and hydrogen, there is 
no essential difference between water and a mixture of these two 
gases. We are told that to speak of the aquosity of water is 
meaningless pedantry, and that to speak of the vitality of living 
organisms is no less so. Of course, if such phrases are offered as 
explanations of phenomena, they are entirely valueless ; but if 
used merely as a kind of shorthand expression of the fact that 
water and living organisms possess certain properties which dis- 
tinguish them respectively from all other bodies, I see no more 
harm in them than in any other technical descriptive terms. In 
neither case can we supply a final explanation of the phenomena 
to which we refer. 

Every stage in the evolution of matter is accompanied by the 
development of new properties or qualities which require the use 
of new descriptive terms. As to the so-called forces which lie 
behind these properties w T e know nothing. We can only classify 
them, as a matter of convenience, according to the effects which 
they produce. We speak of the force of chemical affinity, of the 
force of gravity, of electro-magnetic force, and so on ; and if 
we choose to express our conviction that none of the so-called 
chemical and physical forces are adequate to explain all the 
phenomena of life, there is no logical reason why we should not, 



268 the president's address. 

as a matter of mere convenience, speak of vital forces also. 
Indeed, it appears to me more in accord with scientific method 
to do this than to ignore the existence of such characteristic vital 
phenomena as our own consciousness and intelligence or leave 
them to be explained by supernaturalism. 

After all, the quarrel between the vitalist and the mechanist is 
chiefly over mere terminology. The vitalist knows perfectly well 
that the organism may to a very large extent be looked upon as 
a machine in which chemical and physical processes are utilised, 
and the mechanist knows equally well that he cannot hope to 
explain his own consciousness, and his own intelligent action, 
in terms of chemistry and physics. If we recognise these two 
facts it is a matter of comparatively small importance to decide 
in what terms the unknown factors can best be described. 

At any rate I see no reason why vitalists and mechanists should 
not agree that living organisms first arose, either on our own 
planet or elsewhere, by means of a complex process of physico- 
chemical synthesis, in which the electron, the atom, the molecule, 
the colloidal mult i- molecule and the simplest protoplasmic unit, 
may be taken as representing the chief stages. This at any rate 
is what we should expect from the study of those analytical and 
synthetical processes with which the bio-chemist has familiarised 
us, and from what we know of the process of evolution in 
general. 

What may be the nature of the simplest protoplasmic unit is a 
question still under discussion. That it is not what we commonly 
call a cell seems certain, for a cell has a complex structure which 
must have been preceded by something very much simpler. The 
differentiation into cytoplasm and nucleus, and, above all, the 
extraordinarily complex phenomena of mitotic division, which are 
observable in nearly all cases where a distinct nucleus is present, 
can only have been attained as the result of a long process of 
evolution. The existence of the Bacteria, in which, although 
both cytoplasm and chromatin may be present, there is still no 
properly defined nucleus, perhaps indicates one phylogenetic stage 
through which the fully developed cell may have passed. 

Possibly few biologists of the present day conceive of the most 
primitive organisms as relatively large unnucleated masses of 
structureless protoplasm, such as some of Haeckel's famous 
Monera were supposed to be. " The entire body of these 



THE PRESIDENT'S ADDRESS. 269 

Monera," says Haeckel, "is throughout life nothing more than a 
motile lump of slime without constant form, a small living bit of 
an albuminoid carbon compound. We agree that this homogeneous 
mass possesses a very complex minute molecular structure ; but 
this is not anatomically or microscopically demonstrable. Simpler, 
less perfect organisms are not thinkable." * 

Recent researches, unfortunately, tend to throw considerable 
doubt upon the existence of such Monera. It has been pointed 
out that the failure to recognise a nucleus may have been due to 
the imperfections of microscopical technique at the time when the 
organisms in question were described. Even some of the Bacteria, 
which Haeckel regarded as Monera and which are amongst the 
smallest recognisable organisms, are now known, as we have just 
seen, to exhibit well-marked differentiations in their protoplasm, 
and many of the supposed " cytodes " or unnucleated cells, have 
already been shown to possess a nucleus. With regard to others 
the matter must be regarded as still sub judice. 

Haeckel himself, it must be remembered, recognised the fact 
that his Monera must be composed of ultra-microscopic molecules 
or groups of molecules, which he spoke of as Plastidules or 
Micellae, the latter term having been coined by Naegeli. 

It is these ultra-microscopic and indeed purely hypothetical 
particles of colloidal proteid that the modern biologist is inclined 
to regard as representing the most primitive living organisms, 
and Weismann has gone so far as to assign to them a definite 
place in our scheme of classification, proposing for their recep- 
tion the so-called family Biophoridae and identifying them with 
the biophors or ultimate vital units of his well-known theory 
of heredity. 

It has further been pointed out that such minute particles of 
living matter, far smaller than the most minute Bacteria, may be 
arising all around us by so-called spontaneous generation at the 
present day, without our being able to recognise the fact. It is 
only when, in the course of evolution, they had become aggregated 
in relatively large masses, that we could hope to see them even 
with the highest powers of our microscopes. The justice of this 
view might, however, fairly be questioned. When chemical mole- 
cules arise in our laboratories by combination of atoms or of 

* Translated from Haeckel's " Schopfungsgeschichte," Edition 9 (1898), 
p. 165. 



270 the president's address. 

simpler molecules, they usually present themselves to us in 
aggregates which are large enough to be at once recognisable, 
and one would naturally suppose the same to be true of the 
multi-molecules, biophors, or whatever we like to call them, of 
which living matter consists. As a matter of fact, however, the 
chief objection that I can see to the Monera theory is the 
almost ultra-microscopical size of the simplest organisms actually 
known to us. Indeed, it' we take into account the so-called filter- 
passers, or Chlamydozoa, which are believed to be the germs of 
certain diseases, but most of which we know only by inference, 
we are justified in saying that the simplest known organisms are 
actually ultra-microscopic. 

It seems impossible to obtain any precise information as to the 
size of the smallest particles that can be seen with the microscope. 
Since this address was delivered, Dr. Spitta has been kind enough 
to inform me that he has been able to see and photograph a 
particle only 1/9 7,000th of an inch in diameter, and it will be 
remembered that at a recent meeting of the Club Mr. Brown 
claimed to have seen in the frustule of a diatom a pore the 
diameter of which he estimated at 1/200, 000th of an inch. As the 
filter-passing organisms are ultra-microscopic, they must be smaller 
than this. Indeed, most of them have never yet been seen even 
with the aid of the ultra -microscope, which, by a special method 
of illumination, enables us to recognise the presence of particles 
having a diameter of certainly not more than 1/2, 500,000th of an 
inch and possibly a good deal less, though such particles cannot 
be seen at all in the ordinary way by transmitted light. 

It is only by inoculation experiments that we can prove the 
existence of these ultra-microscopic parasites. Thus we are told 
that if even so small a quantity as 0'005 of a cubic millimetre of 
lymph from an animal suffering from foot and mouth disease 
be inoculated into a healthy calf, the latter will in due course 
contract the same disease, although the lymph, so far as micro- 
scopic examination enables us to judge, is entirely free from 
organisms. 

Yellow fever, cattle plague, rabies and many other diseases are 
believed to be caused by ultra -microscopic parasites. That such 
diseases are due to living organisms and not to lifeless toxins is 
indicated sufficiently clearly by the fact that a period of incu- 
bation always follows infection, during which the poisonous matter 



THE PRESIDENT'S ADDRESS. 271 

increases in amount until there is enough to produce its deadly 
effects, when the characteristic symptoms of disease manifest 
themselves in the patient. 

Buckmaster considers that most of the filterable parasites are 
Bacteria, but as we know nothing of their structure it seems a 
little premature to include them in any group which is based upon 
morphological characters. They might be included in Weismann's 
hypothetical Biophoridae, although, from the point of view of the 
higher organisms, ; ' death -carriers" would certainly be a more 
appropriate name for them than " life-carriers." 

Inasmuch as all the known filter-passing organisms are 
parasitic, it might be argued that their existence implies the 
pre-existence of higher organisms, and that therefore they cannot 
be regarded as themselves representing the most primitive living 
things. Such an argument would, of course, be entirely 
fallacious. It so happens that at the present time the only 
means we have of recognising the most minute of these 
organisms is by their effects upon other organisms. There may 
be hosts of ultra-microscopic organisms living freely on the earth's 
surface which have no recognisable effects upon the higher plants 
and animals, and of whose existence we therefore remain in 
complete ignorance. This would be quite in harmony with what 
we know of the microscopically visible Bacteria. Some of these 
live freely in the soil and are able to feed upon purely inorganic 
substances, while others are far more familiar to us on account 
of their influence, whether beneficial or disastrous, either upon 
ourselves or upon other organisms in which we happen to be 
interested. 

Your late President, Prof. E. A. Minchin, who speaks with 
great authority on such subjects, in his last address to the Club, 
devoted some time to the consideration of the question whether 
the extremely minute organisms which we have be?n discussing 
consist of cytoplasm or chromatin, and pronounced in favour 
of the latter alternative. For my own part I must confess that 
I prefer the view that at this stage of evolution the distinction 
between cytoplasm and chromatin has not yet arisen, a view 
which, as Prof. Minchin pointed out, is in harmony Avith the 
hypothesis of the evolution of living matter from inorganic sub- 
stances on the earth rather than with that of its importation 
from some other planet. 



272 the president's address. 

It follows inevitably from the above considerations that the 
frequent failure of experimenters to demonstrate the occurrence 
of spontaneous generation cannot be regarded as proof that it 
never takes place even at the present day ; much less as proof 
that it has never taken place in the past. 

The classical experiments of Pasteur, Tyndall and other 
observers of the nineteenth century, so far as they related to 
spontaneous generation, seem to have been for the most part 
confined to the problems involved in the occurrence of organisms 
in organic infusions, such infusions being the media in which 
most of the known micro-organisms naturally occur and from 
which they derive their food-supplies. As a result of such 
experiments it is generally believed to have been demonstrated 
clearly enough that if adequate measures are taken in the first 
place to sterilise the culture media by heat, and in the second 
place to prevent the access of living germs after sterilisation 
has been effected, such infusions may be kept for an indefinite 
time without any organisms making their appearance in them, 
and, consequently, without undergoing putrefaction. It is also,. 
I believe, generally supposed, though with little justification, 
that this conclusion applies to all culture media whatever, 
whether organic or inorganic. 

One observer, however, Dr. Charlton Bastian, whose earlier 
experiments were contemporary with those of Pasteur and 
Tyndall, and who has recently been again engaged in similar 
investigations, has consistently maintained a different view. 
His earlier experiments, like those of other observers, were con- 
ducted with organic infusions, or with artificial nutrient solutions 
such as ammonium tartrate or other salts of ammonia. The 
positive conclusions arrived at by experiments with organic 
culture media may be considered to have been completely nega- 
tived by the general experience of bacteriologists during the 
subsequent forty years. 

With regard to the origin of living things from the inorganic 
world, however, the negative results obtained by properly con- 
ducted experiments with organic infusions are of comparatively 
little value. If spontaneous generation takes place at all at 
the present day it probably takes place as it must have done 
at some time in the past, when no organic bodies existed to 
supply food for the first living things. In other words, we 



THE PRESIDENT'S ADDRESS. 273 

should not expect to be able to observe spontaneous generation 
in infusions of organic matter, but should conduct our experiments 
with purely inorganic substances. 

Dr. Bastian's a priori position is a very strong one. If 
spontaneous generation took place once upon the earth's surface- 
there is no known reason why it should not take place to-day, 
while the actual existence of countless hosts of extremely 
primitive organisms alongside the most highly finished products 
of organic evolution certainly seems to support the view that such 
primitive forms are constantly arising from inorganic constitu- 
ents and emerging from the obscurity of their birth only when 
they have reached a stage of evolution at which they are capable 
of appealing directly or indirectly to the human senses. 

Dr. Bastian employed for some of his recent experiments* a 
very dilute solution of sodium silicate, to which was added either 
a minute quantity of pernitrate of iron, or a small quantity of 
phosphoric acid and ammonium phosphate. He joints out r 
however, that the sodium silicate is a variable commercial product 
and attributes to this fact certain otherwise unaccountable 
variations in the results obtained. The experiments were there- 
fore repeated with pure colloidal silica in place of the sodium 
silicate, and positive results were again secured. 

The method of procedure is as follows. The solution to be 
experimented upon is hermetically sealed up in a glass tube 
and heated to about 130 C. for ten minutes or more. After the 
lapse of a few weeks, or in some cases months, during which time 
the sealed tubes have been exposed to ordinary atmospheric 
conditions, they are found to contain living organisms, Torulae y 
Bacteria and even moulds being present in varying quantities. 
Dr. Bastian claims that these organisms have arisen in the 
tubes by spontaneous generation, or, as he terms it, Archebiosis. 
He supposes that the living matter probably originated in 
the first place in the form of ultra-microscopic particles, but 
maintains that in the course of a few weeks or months these 
particles developed into the organisms finally found. 

To a certain extent these results are, as I have already pointed 
out, in accord with purely a ])riori expectations, but in other 
respects they appear improbable to the last degree. Most of the 

* For a full account of these experiments the reader is referred to 
Dr. Bastian's recent book on The Origin of Life. 2nd Edition, 1913. 



274 the president's address. 

organisms produced are of well-known types, and one of the 
moulds formed appears to be a Peniciliium producing spores 
in the ordinary way. I must confess that I myself find it 
impossible to believe without much stronger evidence that such 
comparatively highly organised beings can have been evolved so 
rapidly from ultra- microscopic germs. We are accustomed to 
think of evolution as a very slow and gradual process, and we 
know that Bacteria, Torulae and moulds may be cultivated for 
an indefinite period without undergoing any recognisable change ; 
indeed many industries, such as brewing, wine-making and 
cheese-making, depend for their very existence upon this 
fact. May we suppose that all these organisms have reached 
the limits of their evolution? If so we have the answer to 
the question, why have they remained stationary while other 
organisms have developed into the higher forms of plants and 
animals ? If, however, we are asked to believe that the Bacteria 
and Torulae are stages in the evolution of the moulds, why does 
not this transformation manifest itself in our everyday experience ? 
Dr. Bastian himself, it should be observed, is a convinced 
upholder of the doctrine of heterogenesis, or the sudden appear- 
ance of one kind of organism as the offspring of another, but 
it may be doubted whether any other living biologist holds similar 
views. 

Again, are we to believe that such organisms arise in nature 
under many different conditions and from many different 
mixtures of chemical compounds, or are we to believe that 
Dr. Bastian has accidentally, and almost at the first attempt, 
hit upon just the right materials and the right conditions for the 
production of well-known living things 1 His own observations, 
if correct, show that the experimental solutions may be varied 
within wide limits, but this is hardly what we should expect if 
the origin of living things is to be regarded as a mere stage in a 
series of chemical and physical processes. Another criticism 
of these results may be based upon the fact that the materials 
employed do not (unless accidentally) contain all the necessary 
ingredients of protoplasm. Carbon is apparently entirely 
wanting, and we must either suppose that it is accidentally 
present in minute but sufficient quantities as an impurity, or 
else that it can, as Dr. Bastian actually suggests, be replaced, 
to a greater or less extent, by silica in his organisms. It has 



THE PRESIDENT'S ADDRESS. 275 

been suggested that the colloidal character of the silica employed 
is especially favourable to the evolution of living matter, but 
unless the organisms are largely composed of silica, which is 
highly improbable, it is difficult to see exactly what the colloidal 
silica has got to do with their origin, unless, indeed, it may be 
supposed to act as a catalytic agent. 

Altogether I think we may fairly say that the acceptance 
of Dr. Bastian's results would involve us in so many difficulties 
that it is preferable at present to believe that there has been 
some error in his mode of procedure, some unsuspected loophole 
through which contamination of his preparations has taken 
place.* 

The whole problem looks surprisingly like a modern version 
of the old story with which we started. The question " What 
was the origin of the fossils in the rocks ? " is replaced by the 
question " What was the origin of the organisms in the glass 
tubes 1 ' : We have seen how, in the former case, certain 
statements, made apparently in perfectly good faith, led to 
entirely wrong and absurd conclusions. We are all agreed 
now as to how the fossils got into the rocks, but I am not aware 
that anyone has ever succeeded in explaining the mystery of 
how the marine shells got into the human body, or even how 
the toads got into the stones in which they were alleged to have 
been found. .No one, however, whose opinion is worth con- 
sidering, believes that they were generated there. All are 
agreed that there must have been something wrong with the 
original statements, and there we must be content to leave 
it. It is doubtless premature to say that Dr. Bastian's 
organisms are merely toads in stones, but I do not see much 
to choose between the difficulties of explanation in the two 
cases. The decision must be left to the future, and in the mean- 
time we may console ourselves with the reflection that science 

* Since this address was written Dr. Bastian has published a lengthy 
communication in Nature (January 22nd, 1914) in which he tells us that his 
results have been confirmed by four other observers, two in America and 
two in France. The American observers say, however, " We have no sug- 
gestion to make other than your interpretation, and, indeed, we desire to 
be entirely non-committal as yet." Prof. Hewlett, the well-known bac- 
teriologist, writing at the same time, states that, although he has made 
similar experiments, he has not yet been able to confirm Dr. Bastian's 
results. 

Journ. Q. M. C, Series II. No. 74. 20 



276 the president's address. 

cannot be infallible, but can progress only by a process of natural 
selection, in the course of which one hypothesis replaces another 
in the struggle for existence. The buckets in which we draw up 
truth from the bottom of the well are very small and very leaky, 
and a good deal that is not truth finds its way into them before 
they reach the surface. Fortunately the impurities, even if they 
cannot be eliminated at once, sooner or later sink to the bottom 
and leave the water clear. 



Journ. Quekctt Microscopical Club, Scr. 2, Vol. XII., No. 74, April 1914. 



277 



A CHANGER FOR USE WITH SUB-STAGE 

CONDENSERS. 

By S. C. Akehurst, F.R.M.S. 
Bead October 2Mb, 1913. 

Figs. 1 and 2. 

Petrological microscopes have been fitted in various ways to 
arrange for a quick change of sub-stage condenser, and I have 
frequently felt the need of a similar method applied to a 




Fig 1. 

biological microscope. I found the revolving nose-piece to carry 
three condensers did not work satisfactorily, therefore adapted 
the principle employed in the sliding objective changer to the 
sub-stage fitting, and found this enabled me to get an easy and 
rapid change of condensers. 

The scheme consists of a metal slide 2| x If, with bevelled 
edges, on which the condenser is mounted, and, when necessary, 
a throw-out arm for stops, and an iris diaphragm. Two D-shaped 



278 S. C. AKEHURST ON A CHANGER FOR SUB-STAGE CONDENSERS. 

metal plates, the flat sides of which are set 1| inch apart, form 
a groove for the slide to work in. These plates are screwed to a 
metal collar, the diameter of which is such as to allow the slide- 
condenser changer to be fitted to any microscope that has a sub- 
stage made to the R.M.S. gauge. Fig. 1 shows a plan of the 
slide changer in position, while fig. 2 gives a sectional elevation 
along the line A B, fig. 1. When three, or more, condensers are 
used it is desirable to have each mounted on a separate slide ; 
but when only two condensers are used, one slide may be 
sufficient, as the optical parts can be made interchangeable. 




Fig. 2. 

When the slide with condenser has been pushed home, a screw, 
working through one of the plates, holds this firmly in position. 

This changer does away with the necessity of a throw-out 
sub- stage, and any variation of centrality in the condenser can 
be adjusted by the centring screws in the regular way. 

To rack down the sub-stage fitting, withdraw and insert a new 
slide, are all the movements that are required to obtain a change 
of condenser, and this can be effected as readily as a change of 
objective on a revolving nose-piece. 



Journ. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 74, April 1914. 



279 



A TRAP FOR FREE-SWIMMING ORGANISMS. 

By S. C. Akehurst, F.R.M.S. 

{Bead October 2H(h, 1913.) 

Fig. 3. 

Simply stated this is an arrangement which cuts off the retreat 
of the creatures after they have been attracted into a small 
receptacle by light. 

The first trap I used was made of glass in two pieces. The 
top is funnel-shaped, and holds about 5 ounces of water. This 
is attached to a horizontally-placed cylinder, 1 inch in diameter, 
and 1| inch long the whole being mounted on a stem and foot. 

Into the cylinder is fitted a glass spigot, which has been ground 
in to avoid water passing. There is a hole at the bottom of the 
funnel flask which allows free access of the water to a small well 
in the glass spigot. 

When the trap is working, this well opens immediately under 
the hole at the bottom of the flask, and into this the organisms 
can enter freely. When desiring to fix the catch, give the spigot 
a slight turn the mouth of the well then presses against the side 
of the cylinder and the contents become locked in. 

To set the trap, fill the flask with pond water, cover the entire 
funnel-shaped flask with some light-proof material, and direct all 
the light that can be gathered by a bull's-eye on to the cylinder 
winch contains the glass spigot. Any swimming phototactic 
organism in the water will at once react and pass into the well, 
which is brightly illuminated usually 10 to 15 minutes is 
sufficient to allow for this, but longer time can be given if 
necessary. Give the spigot half a turn, and, as already explained, 
this locks the creatures in the well. The water can then be 
poured off from the flask, the spigot withdrawn, and the rotifers 
or whatever may have been trapped in the well can be taken 
up with a pipette and transferred to the slide for examination. 

After the first catch has been taken the trap can be set again and 
a second lot secured. Work can therefore be carried on without 
interruption or loss of time until all the water has been dealt with. 

Should there be any sediment, this can be allowed to settle and 
then trapped off before any attempt is made to catch the organisms. 

There is difficulty in obtaining this trap made in glass ; I have 
therefore worked out another in metal (fig. 3). This consists of 
a round box, 1 inch in depth, 3| inches in diameter the top and 
bottom slightly convex mounted on a tripod. A hole in the 
bottom allows the water to pass through a short tube, which is in 
three sections, the first part metal, the second rubber and the 
third glass. A pinch-cock can be applied to the rubber con- 
nection, which will prevent water passing when the glass tube 
has been removed for examination of contents. 



280 S. C. AKEHURST ON A TRAP FOR FREE-SWIMMING ORGANISMS. 

I have departed from the funnel shape making the metal 
box to hold the water almost flat, which will allow any sediment 
to settle at the bottom. If the water is very muddy, a cork can 
be fitted into the outlet hole and left until the debris has settled 
first filling the tube with clean pond water. 

If the cork is carefully removed, very little, if any, dirt will 
pass down the tube. Should some slip by, this can be trapped 
off, the tube refilled with water, when a perfectly clear gathering 
can be secured. 

A strainer is provided, to be used, when necessary, for removing 




Fio 3. 



larvae or any of the entomostraca. It is important, that as much 
light as possible should be concentrated on the glass tube. 

To arrange for this a bi-convex lens 1| inch diameter, silvered on 
one side and mounted in a metal holder with a movable support 
allowing it to be tilted at an angle, is placed under the tube, light 
from a bull's-eye condenser is received by the lens and a bright 
beam passed up the tube. This method of transmitting the light 
is very effective, and the trap in consequence acts more rapidly 
and effectively than when the bull's-eye condenser only is em- 
ployed. The lens placed in position is shown in the illustration. 



Journ. QueketL Microscopical Club, Ser. 2, Vol. XII. , No. 74, April iyi4. 



281 



AN IMPROVED FORM OF CHESHIRE'S APERTO- 

METER. 

By Edward M. Nelson, F.R.M.S. 

(Exhibited and described by James Grundy, F.R.M.S., October 28th, 1913.) 

Fig. 4. 

Of the value of Mr. Cheshire's form of Apertometer there can be 
no doubt. The aim of Mr. Kelson has been to enable the N.A. 
of an objective to be read on the Apertometer with greater ease 
and accuracy. 

Distinctness and clearness of reading have been effected by 

APERTOMETER OlAGRAM 
/S. - 1 >nch. 




(ffcfj) 

Fig. 4. 

increasing the number of marked values of N.A. from 9 to 22, 
without the confusion that overcrowding of the lines would entail. 
To accomplish this, short arcs of circles are used instead of whole 
circles. A valuable property of these is the clear visibility of the 
ends or edges of the arcs ; they are seen more distinctly than 
complete circles would be. The contrast between the white 
ground and the short black lines favours this. 

The exterior edges of the arcs denote the N.A., and thus give 
most convenient, accurate and definite positions for reading. 



282 E. M. NELSON, AN IMPROVED FORM OF CHESHIRE'S APERTOMETER. 

The first or lowest marked value is 0'05 N.A., and the values 
increase by increments of 0'05 up to 0'5 N.A. From 0*5, the 
values increase by 0*033 up to 0*9 N.A. 

The apparatus consists of an Apertometer diagram (fig. 4) 
printed on a small card about the same size as Mr. Cheshire's 
form, another card of explanations and instructions, a cubic inch 
of wood and a metal diaphragm with a hole not more than 
1*25 mm. in diameter. Mr. Nelson lays some stress on the hole 
in the diaphragm being not more than 1'25 mm. in diameter. 
He says: "If the hole is larger than that, some objectives, 
especially low powers, will read a great deal too high. And 
accuracy is, relatively, more important with the small apertures, 
because for example an error of O'Ol or 0*02 will make a far 
greater percentage of difference than it would with, say, the 
N.A. of an oil-immersion objective. If 1*25 and 1*27 be com- 
pared with the N.A. 0*11 and 0*13 of a 3-inch objective, the 
actual difference between the two pairs of values is 0*02 in each 
case, but the percentage difference with the higher N.A. is only 
1*6 as compared with 18 in the case of the low values." 

In this connection, Mr. Nelson has made another important 
remark, namely, " The working aperture is larger than the 
correctly measured true aperture, so that low powers resolve more 
than they are entitled to theoretically. This is probabhy due to 
the practically enlarged aperture caused by the rolling motion 
of the eye from side to side." 

It will also be noticed that the diaphragm to be used with the 
apertometer is made convex on one side, and if the convex side 
is put into the larger aperture of an eye-piece or other 
diaphragm, it rests steadily in position. 



Journ. Quekett Microscopical Club, Ser. 2, Vol. XII. , Ko. 74, April 1914. 



28 



n 



TWO SIMPLE APERTOMETERS FOR DRY LENSES. 

By Frederic J. Cheshire, F.R.M.S. 

{Read October 2$th, 1913.) 

Figs. 5 amd 6. 

In dealing with questions of apertometry it is very important to 
inquire, in the first place, as to what order of accuracy it is 
desirable to work. No useful purpose would be served by giving 
a carpenter a foot-rule, divided to hundredths of an inch, with 
which to measure the length of a plank. The measurement, 
if made to such an order of accuracy, would be useless and 
meaningless. 

Prof. Abbe, in " Some Remarks on the Apertometer" {Journal 
of the Roy. Jlic. Soc. 1880, p. 20), after stating that the error of 
measurement in his well-known apertometer is limited to about 
| per cent., goes on to say that "an exactness of reading 
to this extent is evidently more than sufficient. An unavoidable 
amount of uncertainty resulting from the nature of the object, 
and many other sources of slight error, will always limit the 
real exactness of observation beyond 1 per cent, of the unit, 
different observers and different methods of equal reliability 
being supposed. In low powers slight variations in the length 
of the tube, in high powers slight alterations of the cover- 
adjustment, will admit of much greater difference than the 
error of reading will introduce. It should be observed that 
in high-angled objectives the aperture has not the same 
value for different colours, owing to the difference of focal 
length (or amplification), even in objectives, which are perfectly 
achromatic in the ordinary sense. In the case of very large 
angles, the aperture, angular or numerical, will be greater for 
the blue rays than for the red, generally by more than i per 
cent. Last, not least, there is no possible interest, either 
practical or scientific, appertaining to single degrees, or half 



284 F. J. CHESHIRE, TWO SIMPLE APERTOMETERS FOR DRY LENSES. 

degrees, of aperture angles ; for no microscopist in the world will 
be able to make out any difference in the performance of objec- 
tives as long as the numerical apertures do not differ by several 
per cent., other circumstances being equal." 

" For these reasons I consider all attempts at very accurate 
measurements of this kind to be useless." 

No one, probably, is likely to have the temerity to question 
the authority of Prof. Abbe on such a question as Apertometry, 
so that we can accept his limit of 1 per cent, with confidence. 

Fig. 5 shows a plan of a form of apertometer for dry lenses 
which for simplicity in use and for the accuracy of its results 
probably leave nothing to be desired. A strip of vulcanite A * 
is so divided that the distance D of any line from the zero of the 
scale is given by the equation 

D = 2 A tan (sin-i n.A.) 

set out in this Journal for April 1904 (Ser. 2, vol. ix. p. 1), in 
the article on " Abbe's Test of Aplanatism, etc." The graduations 
are marked with the corresponding N.A. values for a value of A 
equal to 25 mm. In use the apertometer is placed upon the 
.stage and the object plane of the lens to be tested adjusted at a 
height of 25 mm. above the plane of the scale. The upper focal 
plane of the objective is then observed in any known way and the 
apertometer adjusted on the stage until the inner edge of the 
fixed white block B is seen on one edge of the objective opening. 
This adjustment effected, the sliding white block C is slid along 
the strip A until its inner edge is seen on the opposite edge of the 
objective opening to that on which the block B is just seen. 
The N.A. value found opposite to the inner edge of the block 
on the scale is that of the lens tested. 

The graduations from to 0*9 N.A. proceed by steps of 0*02 
and from 0-9 to 0*96 N.A. by steps of 0-01. 

Fig. 6 shows a modification of the form of apertometer 
described in my original paper in 1904. I have substituted for 
the concentric circles there shown curved lines which project 
optically into the upper focal plane of the lens being tested as a 
number of equi-distant straight lines of equal thickness. The 
projected image of the apertometer scale is thus a simple linear 

* The right-hand end is shown broken off. 




o 



6 





II 
<l 



U 
h 

- 

o 

<r 
ai 
a 
< 

en 

a 

I 

00 

UJ 

I 

O 




O 





QQ 



286 F. J. CHESHIRE, TWO SIMPLE APERTOMETERS FOR DRY LENSES. 

scale upon which N.A. values can be read directly. The scale 
runs from 00 to 0*9 N.A. by steps of 0*05, i.e. the divisions 
starting from the centre have the values 0, 0'05, 0"10, 015, - 20, 
etc., of N.A. 

The short curved lines of the scale should strictly be hyperbolas, 
but such curves are very difficult to draw accurately, and it was 
not until my son, Mr. R. W. Cheshire, suggested to me that they 
might be replaced by arcs of circles with curvatures equal to 
those of the corresponding hyperbolas at their vertices that the 
apertometer described became a practical construction. 

I may, perhaps, be allowed to avail myself of this opportunity 
to say that in my opinion there are several objections to 
Mr. Nelson's form of the Apertometer which was introduced 
by me in 1904. These may be briefly indicated. In the first 
place, no advantage can result from the use of the outer edges 
of the lines, instead of the middles, as is usually done, as the 
part of the lines from which distances and therefore NA.'s 
must be estimated by eye. Further, in Mr. Nelson's form the 
thickness of the lines varies in different parts of the diagram, 
and has no assigned or stated thickness in terms of N.A. This, 
I think, is a fatal defect, because when the thickness of a line 
has a N.A. value of - 02, say, such thickness, especially when 
dealing with low-power lenses, provides an invaluable standard 
of reference when estimating by eye N.A. values intermediate 
to those represented on the scale. 

In apertometers of the kind in question the further the sub- 
division of the scale is carried the greater must be the complexity 
of the image presented to the eye the advantage of one is 
balanced by the disadvantage of the other. Possibly, however, 
most people would prefer the simplicity of a diagram with the 
larger divisions to the optical Hampton-Court-maze necessitated 
by the smaller ones. 



Joum. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 74, April 1914. 



287 



A VARIATION OF CHESHIRE'S APERTOMETER. 

By M. A. Ainslie, R.N., B.A., F.R.A.S. 
.(Read October 2Sth, 1913.) 

Figs. 7 and 8, 

Experience in the use of both the original forms of Cheshire's 
Apertometer, and the modification thereof recently introduced 
by Mr. E. M. Nelson, has revealed one or two difficulties in 
connection with the reading of the instrument that is, if any 
accuracy in the second place of decimals is required and the 
present instrument is an attempt at removing these. 

The first difficulty is due to the fact that in Mr. Cheshire's 
instrument we have to interpolate or estimate between two 
divisions on a scale, one of which is not visible, being outside 
(apparently) the margin of the back lens of the objective, This 
renders the estimation of the second place of decimals in the 
N.A. uncertain, and although Mr. E. M. Nelson's modification 
of the original instrument is somewhat better in this respect 
yet the very means adopted to improve the reading, namely, 
the introduction of a large number of additional circles is 
likelv to confuse the diagram and bewilder the observer. 

In either the old form or the new of Cheshire's instrument, 
a count has to be made of concentric circles ; a thing which, 
simple as it may seem, is peculiarly liable to confuse the eye ; so 
that it is only after counting several times that one feels certain 
that the number is, say, eight and not seven. In the present 
instrument a totally different method of reading is adopted ; the 
diagram is simplified, and the estimation of the second place of 
decimals is merely the estimation of the point where a spiral 
curve cuts the margin of the back lens of the objective, referred 
to two points, one on each side, where radial lines cut the 
same. 

The instrument, which consists, in the form for dry lenses, 



288 M. A. AINSLIE ON A VARIATION OF CHESHIRE'S APERTOMETER, 

of a card diagram placed on the stage, is constructed as follows- 
(% 7): 

A series of radial lines are drawn from a common centre, 
making equal angles with one another ; the precise number is- 
immaterial, but it has been found convenient to divide the circle 
into sixteen equal parts. One of these (preferably that lying^ 
horizontally) is selected as a zero, and points are marked off 
along the others at distances equal to a constant length (usually 
25 mm., or 1 inch) multiplied by the tangent of the semi-angle 
of aperture ; i e. the tangent of the angle whose sine is the- 
numerical aperture. This is done for every (H of N.A., and 
a spiral curve drawn through the points thus obtained ; this. 




Fig. 7. 



curve being repeated, turned through 180. The curves are 
shown with fair accuracy in fig. 7. 

The diagram is used precisely as the Cheshire Apertometer : 
either the objective is focused on the upper surface of a cube of 
wood as in the Cheshire instrument ; or else a pinhole in the 
centre of the diagram is focused, and the body racked back 
25 mm., or 1 in., this being measured easily enough with a 
scale. This latter method is preferable for objectives of high 
aperture. A |low-power eye-piece is employed. On examining 
the Ramsden disc with a hand lens (a watch-maker's eye-glass 
does well) the appearance in fig. 8 is seen, and the method of 
estimating the value of the N.A is fairly obvious ; we have only 
to start from the zero and count in the direction of the spiral, 



M. A. AINSLIE ON A VARIATION OF CHESHIRE'S APERTOMETER. 28i> 

(H for each radial line passed over ; the second figure is found by 
estimating the position between two adjacent radial lines of the 
point where the spiral cuts the margin of the back lens. In 
tig. 8, for example, the N.A is about - 73. 

The procedure is the same with the form suited to immersion 
lenses ; the upper surface of a plate of glass is focused, and the 
diagram is balsamed to the lower surface. It might be pre- 
ferable to have 12 radial lines instead of 16, and read like 
a clock ; this is a matter for experiment. 

Of course the value of the radius vector of the curve for 
a diagram in optical contact with glass will not be quite the 
same as before ; instead of r = C tan <, where sin < = N, we 




8 



Fig. 8. 



shall have r = C tan <' where /x sin <' = N\ but the principle 

is the same. 

The equation to the curve presents some interesting features; 

aO 

where C is the distance of the diagram 



it is r = Cr_ 



V 1 a 2 2 

from the lower focal plane of the objective and a is a constant 
depending on ll and on the number of radial lines in the circle ; 

for 16 radial lines, and /x = 1 (dry form), a = ^ . The radius 

representing N.A. = I/O is obviously an asymptote to the curve ; 
in the case of the glass form, N.A. = /x will be the asymptote. 

It is of interest to note that the same curve will serve for any 
refractive index of the medium beneath which it is mounted : if 



290 M. A. AINSLIE ON A VARIATION OF CHESHIRE'S APERTOMETER. 

we change the refractive index from 1 to ju, we merely have to 
close up the radial lines in that ratio, leaving the curve unaltered. 
For instance, if we had 16 radii for the dry form we could use 
the same curve, but with 24 radii, for a plate of glass of 
fx = 15. 

In practice the instrument proves of great utility, and very 
reliable and easily used. All that is necessary is to be accurate 
in centring ; this is easily seen to be correct when the reading of 
each end of the spiral is the same. 






Journ. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 74, April 1914. 



291 AfclC 







ON THE DISC-LIKE TERMINATION OF THE 
FLAGELLUM OF SOME EUGLENAE. 

By James Burton. 

(Bead November 25th, 19130 

About two years ago, one of our members Mr. Ellis was 
exhibiting here living Euglena viridis. During the evening the 
creatures, presumably affected by the light, heat and confine- 
ment of the life-slide, threw off their flagella ; it was perhaps a 
preparatory step to encystment, or even to their death, under 
the unnatural conditions of their environment. In the field of 
the microscope there were numbers of these organs floating 
free, and in the case of many of them, if not quite the ma- 
jority, they were terminated by what appeared to be a small 
disc or bulb. We were greatly interested in the phenomenon, 
and decided to investigate it. Mr. Ellis soon after wrote a 
letter to The English Mechanic, describing what he had seen, and 
inquiring if any one else had had a similar experience. There 
were no very definite answers, no one claiming to have noticed 
this occurrence before. In his letter he says : 

" On turning on the one-sixth, something quite out of the 
ordinary at least, to me was seen in the shape of minute 
transparent discs, each with a long, thick, but motionless fla- 
gellum, and apparently associated with the resting Euglenae, 
around which they appeared most plentiful. For some time I 
was puzzled to account for these objects, until, noting the 
obvious similarity in length and thickness between their flagella 
and those of the motile Euglenae, I became convinced they were 
one and the same, they having been thrown off* bodily by the 
exhausted Euglenae, and not retracted as is usual, I under- 
stand." . . . " Now here comes the difficulty : What is the little 
disc to which the flagellum is attached ? Is it the ' knob-like 
inflated distal extremity ' of a flagellum belonging to 'an interest- 
ing local variety of E. vi?'idis' described by a writer in Science 
Gossip for October 1879, and referred to by Saville-Kent on 
p. 382 of his ' Manual of the Infusoria,' and illustrated on 

Jourx. Q. M. C, Series II. No. ~. 21 



292 J. BURTON ON THE DISC-LIKE TERMINATION OF THE 

PI. xx. fig. 29 ? " Saville-Kent says, in the paragraph referred to : 
" An interesting local variety of E. viridis has been recently 
described by Mr. M. H. Robson, of Newcastle-upon-Tyne, in 
which the distal extremity of the flagellum presents an inflated 
knob-like aspect, as shown at PI. xx. fig. 29. Possibly such 
modification of this important organ represents a phase pre- 
liminary to its entire withdrawal, and antecedent to the 
entrance of the animalcule upon the encj 7 sted or resting stage." 

In Science Gossip (1879) there are several letters about the 
phenomenon, one on p. 231 by Mr. Robson, with the original 
drawing from which Saville- Kent's figure is taken, and also two 
other forms of Euglenae with identical organs. Referring to 
them, Mr. Robson says: "These may be of interest, as I, at all 
events, have not met an observer who has previously noted this- 
peculiarity." In a letter on p. 136 another writer mentions a 
case where in a large number of Euglenae " the flagellum was in 
each case bulbed." And he draws the singular conclusion that 
these were not true Euglenae, but suggests they may have been 
a larval form of the rotifer Hydatina senta. In a letter, p. 159,. 
Mr. Robson writes of E. viridis and its " sucker bulb," and of the 
existence of " the bulb siphon, sucker, or whatever it is." On 
p. 256 there is a letter from Mr. George headed, " E. viridis and 
its bulbed flagellum," and he makes reference to the fact that 
" on one occasion, whilst closely watching the contortive move- 
ments of a full-grown specimen, I was much surprised to see the 
little animal ' bite off",' if I may so term it, the flagellum, which 
immediately floated away." It is clear at least from all this that 
observers a good many years ago saw the structure, and that it 
created a good deal of interest and some speculation as to the true 
interpretation of the appearance. 

Now, to return to Mr. Ellis's question, " What is the little 
disc " attached to the distal end of the flagellum of some 
Euglenae ? After some considerable attention to the subject,, 
and observation of many examples, I have come to the conclusion 
that there is no disc, no bulb or sucker, or anything of the kind 
at the end of the flagellum. The appearance which has given 
rise to the idea can be correctly accounted for in another 
manner. I have often seen the disc since Mr. Ellis first called 
attention to it, but do not remember ever seeing it on a flagellum 
in active use by a healthy Euglena ; in fact, it is almost impos- 



FLAGELLUM OF SOME EUGLENAE 293 

sible to see the flagellum at all when the creature is in full vigour 
it is then usually being lashed about, and is bent and twisted in 
all directions. It will be noticed that Mr. Ellis only claims to 
have seen the disc when, for some reason, the organ to which it 
was attached was thrown off. 

He says : " Out of all the numberless motile Euglenae which 
were swimming about amongst their resting kindred, not one was 
seen with a flagellum having a knob at its free extremity." 

Neither do I think any of the writers in Science Gossij) dis- 
tinctly claim to have seen it on a healthy, active animal. But 
when the flagellum is thrown off " bitten off," as has been 
described or when the Euglena is killed by a careful application 
of iodine, it is not at all infrequent, and I have seen it on speci- 
mens from many different localities. 

It happened that since I thought of bringing the subject 
before you I was looking over, for quite another purpose, a slide 
of Euglenae mounted in April 1911. I there found several 
instances of discs still attached. Some creatures, and some 
Euglenae at all events, occasionally carry the flagellum stretched 
out rigidly in front, with a small portion of the distal end thrown 
into a coil or spiral form, usually rapidly moving. Now if the 
creature were killed with the organ in that position, or for any 
reason threw it off, it seems to me very probable that the coil 
there might be but one turn in it would present just the 
appearance we have had referred to as a disc or bulb, and that, 
consisting of protoplasm, it would be very likely to adhere where 
touching another part, and so retain its form as a circle. With 
the use of an immersion objective and careful illumination, it has 
seemed to me possible to make out a part of the circle as being 
thicker or darker than the rest, owing to the thread overlapping 
at that point. It must be remembered that we are dealing with 
a very small and very transparent structure, not easy to demon- 
strate correctly. Moreover, among the others, killed by iodine 
or mounted, it is easy to find specimens with the flagellum much 
twisted and thrown into " kinks." So that there are often small 
circles at the sides instead of at the end of the thread, and 
although these have just the same appearance as those at the 
end, I do not think any one would suggest that it is likely a disc 
or bulb would occur in such a situation, to say nothing of the 
im probability of there being more than one, and these often on 



294 J. BURTON ON THE FLAGELLUM OF SOME EUGLENAE. 

opposite sides. These would be put down at once as loops or 
kinks and I believe the so-called terminal disc or bulb is of the 
same nature, but it is more striking and more deceptive, owing 
solely to its position. When I told Mr. Ellis of the conclusion I 
had come to, he was at first disinclined to accept it, but after- 
wards, I think, did so fully. If I am right, the subject is merely 
an instance of correct observation but incorrect deduction from 
it in fact, an error of interpretation, quite a well-known occur- 
rence to microscopists ! Perhaps, indeed, the matter would hardly 
justify particular reference to it, had not the figure and the note 
read appeared in Saville-Kent's Manual a work whose value to 
us all gives it an importance and authority which must be my 
excuse. 



Joura. Que/cett Microscopical L'lub, Ser. 2, Vol. XII , A'o. 74, April li'14.. 



205 



ON THE MEASUREMENT OF THE INITIAL MAGNI 
FYING POWERS OF OBJECTIVES. 

By Edward M. Nelson, F.R.M.S. 

{Read November 25th, 1913.) 

Fig 9. 

The majority of uiicroscopists only concern themselves with the 
total magnifying power of their microscopes, but some wishing to 
probe further into matters want to know the initial power of their 
objectives. 

The initial magnifying power, m, of an objective is -7-, but the 

focal length (f) of an objective is a very difficult thing to measure 
directly. Usually it is found by an indirect method of measuring 

the magnifying power, for, as above, = /. 

Probably the best way of measuring the focal length by the 
indirect method is to project the image of a measured object, 
placed 100 inches from the stage, and to measure the diminished 
image at the focal point of the objective by means of a microscope, 
fitted with a screw micrometer ; the magnification, m, thus 
obtained will give the focal length with great accuracy, for 

f ~ z. As the numerator is 100, the result can be found in 

nt 4- 'Ji 

a reciprocal table, without the necessity of doing a division sum. 

Simple as this seems, it is however a troublesome thing to do ; 
but by the method here described the initial power, and hence the 



296 E. M. NELSON ON THE MEASUREMENT OF THE 

equivalent focus of a microscope objective, can be quickly and 
easily measured. 

The apparatus required is a stage micrometer and a screw 
micrometer with a positive eye-piece. With a tube of a length 
as described below, the interval of two divisions of the micro- 
meter scale on the stage is read on the drum of the eye-piece, 
and this reading will be the initial magnifying power of the 
objective. 

The only difficulty here is the determination of the proper 
tube length. The tube length is to be measured from the 
web in the eye -piece to the end of the nose-piece of the 
microscope. 

The formula for the determination of the tube length is 

15 \/ - -f- 0335, where p is the nominal initial power. Example: 
V 

The initial power of a half-inch is required. The nominal 
power of a half-inch is 20, which is p, then 15 A/ + 0*335 = 

15v/0-385 = 15 x 0'62 = 9*3 inches tube length. 

The tube must be drawn out until the web is 9 - 3 inches from the 
nose-piece, and, with the half-inch on the nose-piece, two y^^ths 
of an inch divisions on the stage micrometer are spanned by the 
webs. The drum then is read, say, 22*4, and this is the initial 
power of that half-inch, without any further calculation; its focal 

length is ip^ ov Q'^Afi inch. 

In case the nominal initial power is unknown, it is first deter- 
mined with, say, a 9^-inch tube, the value thus found is inserted 
in the equation and the measurement made again with the 
correct tube length. All powers of quarter-inch and less focus, all 
Zeiss's apochromats of whatever focus, and other makers' apoch- 
romats, require a 9-inch tube. 



INITIAL MAGNIFYING POWERS OF OBJECTIVES. 



297 



For lower powers the accompanying table, computed by the 
above formula, gives the necessary tube length. 

It must be noted that it has been assumed that the screw 
micrometer with the positive eye-piece is an English one, with 
50 threads to the inch, but if it is a Continental one, with a 
millimetre thread, a millimetre stage micrometer must be used, 
and the proper number of divisions measured. If it is found that 
the magnification is so high that two divisions cannot be spanned 
by the micrometer webs, then obviously one division is measured 
and the reading is doubled.* 

TABLE. 
0, objective ; N, nominal power ; T, tube length in inches. 






N 


T 




O 


N 


T 




o 


12-3 


1 


10 


9-9 


3 


3-5 


11-8 




3 
4 


12 


9-7 




4 


11-5 




2 
3 


15 


9-5 




4-5 


11-2 




1 
2 


20 


9-3 


2 


5 


11-0 




4 


25 


9-2 




5-5 


10-8 




1 
7J 


30 


9-1 




6 


10-6 






35 


9-05 


1| 


7 
8 
9 


10-4 
10-2 
100 




1 


40 


9-0 



Let me again impress upon microscopists to measure, or get 
measured, the optical indices of their objectives. The optical 
1000 N.A. 



index is 



m 



Photographers have the same thing in their 



//4, //16, etc. No photographer would think of paying as much for 
a lens of f/lQ as he would for one, of similar focus and qualitv, of 
fji) then why should a microscopist? A microscopist, for example, 

The foci of a large number of all sorts of microscope objectives, which 
had been previously accurately determined by the long method, were 
remeasured by this new short method ; the results obtained were so 
satisfactory that now only the short method is used. 



298 E. M. NELSON ON THE MEASUREMENT OF THE 

buys a T *oth objective of 0"65 N.A. Here an optical index of 26 - 
is implied ; when he gets home he measures it and finds it |rd of 
055 N.A. with an optical index of only 18*3, or 30 per cent. less. 
This is not an exceptional case, but one which unfortunately 
exemplifies the usual practice. Messrs. Zeiss have for long set an 
excellent example by never sending out lenses below either their 
catalogued N.A. or shorter foci. I have measured scores of them 
and have found their optical indices often in excess, and seldom 
if ever in defect. 

[The method of determining the focal length of an objective, 
by the indirect method from the magnifying power, may not be 



A 



t 



B 



L too inc\e& _^ 

i 



c 






Mr 



r 



s 

Fig 9. Diagram to show Relative Positions of the Apparatus. 

M Microscope tube. P> Objective. 

A Screw micrometer. C Objective to be measured, in substage. 
S Microscope stage and micrometer. 

quite clear, hence the following particulars from notes received 
from Mr. Nelson may be useful. His own words are practically 
as follows: The microscope is placed horizontally; a low- power 
objective, 3, 2, or 1| inch, according to circumstances, is placed 
in position ; screw-micrometer eye-piece ; the objective to be mea- 
sured is placed in substage, with its front lens facing the stage. 
A card cut to the pattern as shown in figure (fig. 9) is fixed by 
means of a clip in front of the window : the card should be 
placed at the exact measured distance of one hundred inches 
from the stage of the microscope. 



INITIAL MAGNIFYING POWERS OF OBJECTIVES. 209 

The stage micrometer is placed on the stage, and the constant 
of the screw-micrometer determined. The focus of the micro- 
scope is not to be disturbed, but, by means of substage focusing, 
the lens to be measured is racked up until the image of the card 
is sharply focused. Then one of the sides of the card is spanned 
by the webs of the eye-piece micrometer, and its size measured 
and the magnifying (or rather diminishing) power found : then 

._ 100 
~~ m + '2' 

Of course, the idea of the 5 inches is that the reading is 

doubled, and then 10 -t- x (say), gives the magnification, m, which 

can be found from reciprocal tables, as well as the value of 

^ ' 1,1 + T 

It is not difficult, but a little more trouble, to make the calcu- 
lations without tables. 

For the benefit of photomicrographic members, the following 
is quoted from a note by Mr. Nelson. " This method will 
measure the foci of large photographic lenses. In that case 

,_ 100 _ 100 

m + 2 (m + If 

" This second term is only necessary when f is large compared 
with one hundred inches ; for microscopic lenses it is not wanted. 
The whole can be determined from reciprocal tables without 
putting pencil to paper." The tables referred to are those of 
Barlow, published by Messrs. E. & F. N. Spon. 

The screw-micrometer eye-piece is, perhaps, a drawback. Mr. 
Nelson says, "An ordinary screw-micrometer with a negative 
eye-piece is no good for lens measurements ; the eye-piece must be 
of the Ramsden type, and it is very doubtful if any ordinary 
ruled glass micrometer eye-piece would be sufficiently accurate. 
A screw-micrometer is necessary for both the methods described 
in the paper." 



300 E. M. NELSON ON INITIAL MAGNIFYING POWERS OF OBJECTIVES. 

It will be noticed that Mr. Nelson lays stress on what he has 
named the Optical Index ; but perhaps it is less apparent that 
this paper on the magnifying power of objectives, and his com- 
munication to the last meeting on their aperture, are quite 
closely related to the Optical Index in fact, they deal with both 
the values involved in the formula for the Optical Index of an 

, . .. Numerical Aperture x 1,000 

objective = A ^ . 

Magnifying .rower 

A general way of expressing the meaning of the Optical Index 

of an objective is that it is the ratio of its aperture to its 

power. J. Grundy.] 



Joura. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 74, April 1914. 



301 



SOME OBSERVATIONS CONCERNING SUB-STAGE 

ILLUMINATION. 

By S. C. Akehurst, F.R.M.S. 

(Bead January 27th, 1914.) 

Plates 20-22. 

The accepted method, and the one generally used, for sub-stage 
illumination is that known as the solid cone of light, controlled, 
within certain limits, by the iris diaphragm. Another form that 
is, annular light is occasionally used, but is not considered by 
many microseopists to be of value for critical work. 

Both these forms of illumination are too well known to need 
detailed explanation. The textbooks, however, have very little 
to say either for or against the latter method, excepting Cross and 
Cole, 3rd edition, where a definite statement in favour of annular 
light is to be found. I cannot do better than quote this : " Stops 
can be further used for strengthening the contrast in the image 
with large cones of illumination and objectives having high 
apertures. This method does not minimise in any way the 
effective working of the objective, for, with objectives of large 
aperture, rays may be present which only impart brightness to 
the field, but do not contribute to making visible the fine detail 
upon the object. If less than half of the lateral spectra are seen 
on looking down the tube at the back lens of the object glass with 
a striated object in focus, then the central portion of the direct 
beam or central disc has no lateral image corresponding to it in 
the portions of the spectra that are visible. Under these circum- 
stances, that central portion of the central disc in no degree 
contributes in enabling the detail to be seen, but only produces a 
haze ; by blocking it out the haze is removed and there is a great 



302 S. C. AKEHURST ON SOME OBSERVATIONS CONCERNING 

improvement in the resulting definition." Mr. J. W. Gordon's 
opinion is that when a suitable stop is employed in the sub-stage 
condenser there is no objection to using annular light with an oil- 
imniersion objective of high numerical aperture. It is, however, 
necessary that the outer zones of the objective used should be 
well corrected. His own method of blocking out the central 
beam is to use a stop over the eye-piece and this is fully described 
in the Journal R. M. S., February 1907. On the other hand, 
Carpenter does not entirely agree that annular light is permissible. 
Quoting from the seventh edition, he says, " If it is required to 
accentuate a known structure, such as the perforated membrane of 
a diatom, it can be done by annular illumination, which means 
the same arrangement as for dark-ground but with a stop insuffi- 
ciently large to shut out all the light. This method is not to be 
recommended when a structure is unknown, as it is also liable to 
give false images." 

Mr. Nelson has also expressed himself against annular light, 
stating that whilst strong resolution of diatoms is obtained by 
this method of illumination it also gives rise to spurious images. 

The subject of sub-stage illumination is a large one, and I am 
only dealing with one phase of it, viz. annular light produced by 
a reflecting condenser, to be used in conjunction with an oil- 
immersion objective, for resolving the fine structure of diatoms 
and displaying stained bacteria.* When a wide-angle refracting 
condenser is employed, with stop to produce annular light, trouble 
arises through chromatic aberration, which is especially noticeable 
when an objective of high aperture is used. This dispersed colour 
is objectionable, as it operates against a pure image being formed, 
and is also detrimental to obtaining faithful records by photo- 
graphy. Much has been undertaken to demonstrate that, in 
practice, light from a condenser exhibiting chromatic aberration 

* A slide of Tubercle bacilli was exhibited illuminated with annular 
light, showing that the reflecting condenser works well with small stained 
objects in addition to diatoms. 



SUB-STAGE ILLUMINATION. 303 

does not prevent good work being accomplished. On the other 
hand, I believe the reduction of chromatic dispersion to a minimum 
leads towards an ideal system for critical work. 

The question now arises, if annular light is employed with 
objectives of high aperture, how is the trouble arising through 
chromatic aberration to be avoided. I suggest reflected, instead 
of refracted, light being used. I came to this conclusion after 
makincr a number of observations with a Leitz concentric reflect- 
ing condenser. This condenser has two reflecting surfaces, one 
convex and the other concave, and, as the rays are brought to a 
focus by reflection only, there is no chromatic dispersion, and 
spherical aberration is reduced to a minimum. The elimination 
of spherical aberration, however, is not a matter of importance. 
This was pointed out to me by Mr. J. W. Gordon, who has very 
generously allowed me to make use of his remarks on this point. 

He says: "Light from the periphery of the condenser may 
exhibit defects due to spherical aberration. This light, on reach- 
ing the object, sets up a new impulse, and the rays emerging from 
the object, and travelling towards the eye, will, in any plane con- 
jugate to the plane of the stage, appear free from the original 
defects of spherical aberration just as if they had started from 
an independent source. No false images would, therefore, arise 
from this cause in the image plane when light is used from a 
sub-stage condenser that has not been corrected for spherical 
-aberration." It should be carefully noted that this reflecting con- 
denser was produced to obtain dark-ground effects, and was never 
intended to be used in the manner I have employed it that is, in 
conjunction with a T V inch oil-immersion objective without a funnel 
stop to reduce the IS". A. of the objective. In its present form the 
reflecting condenser I have passes too much light. The results 
obtained, however, were sufficiently striking to arrest attention 
when resolving fine structure of various diatoms. The transverse 
striae of Amphlpleura pellucida in monobromide of naphthalin 
were displayed. In realgar the same details were strongly shown, 



304 S. C. AKEHURST OX SOME OBSERVATIONS CONCERNING 

and when the mirror was slightly tilted, if the diatom was a 
suitable one. it was resolved into dots. A good image of the 
rosettes on Coscinodiscus asteromphcdus was obtained, which 
stood a high-power eve-piece well. With the mirror slightly 
tilted, the faintly marked transverse striae were visible on Cymato- 
pleura solea also an excellent black-dot image was displayed of 
Xo.ck'da rhomboid.es, SurireUa gemma and Pleurosigma angu- 
IcUuin. On examining a strewn slide of Xacicula r~homboid.es 
in realgar I found a specimen of Pinnularia nobilisl On tilting 
the mirror and obtaining oblique light the costae were filled with 
dots. Particulars of this were forwarded to Mr. Nelson, who 
replied as follows: "Mr. Merlin and I have seen the structure 
on Pinnularia to which you refer. It was demonstrated upwards 
of twenty years ago by H. Gill, who tilled up the apertures in 
diatoms with platinum some of these specimens I have still." I 
am pleased to be able to give this report, as it helps to dispose of 
the idea that might arise that the dots displayed were probably 
due to false images, brought about by using annular light. 

The opaque lines on an Abbe test plate were well defined, and 
an excellent rendering of stained bacteria, such as Tubercle bacilli,, 
was obtained. In all the tests referred to the following combina- 
tion was used : Incandescent gaslight, Nelson stand condenser, 
Leitz concentric reflecting condenser and tiuorite, T Vth inch oil- 
immersiun objective N.A. 1*35, Wiukel complanat eye-piece, and 
Wratten B screen. 

During the autumn of 1913 Mr. O'Donohoe became interested 

in this reflecting condenser, and he spent an evening with me 

examining some of the test objects referred to ; and afterwards 

kindly undertook to see if any results worth attention could be 

obtained by photography when using this type of condenser. He 

was successful in getting a record of the dots on Pinnularia.* 

I am very much indebted to Mr. O'Donohoe for the ready 
manner in which he undertook the work of testing the condenser, 

* T. A. O'Donohoe : "An Attempt to Resolve Pinnularia xobilis,'' p. 309. 



SUB-STAGE ILLUMINATION. 305 

and for the photographs which illustrate this paper ; and you 
will agree with me that without these records my remarks con- 
cerning the value of reflected annular illumination would have 
been much less convincing. 

Summary of the Advantages in using Annular Light 
produced by reflecting condenser. 

(1) When employing an achromatic condenser excess of light 
is reduced by closing the iris diaphragm. This involves a sacrifice 
of the numerical aperture, and, therefore, loss of resolution. 
With the reflecting concentric condenser there is no loss of high- 
angle rays, the excess of light being modified by stopping out a 
portion of the central or dioptric beam; the fullest possible 
advantage can, therefore, be taken of the numerical aperture of 
the whole optical system. 

(2) Chromatic dispersion being entirely eliminated, a pure 
image is obtained. 

(3) The absence of colour in the field admits of critical work 
being done by photo-micrography. 

(4) When necessity arises to search a slide for minute striae, 
or other fine structure, it is immaterial in which direction across 
the field the striae appear they are resolved. 

(5) The simple construction of this type of condenser admits 
of it being produced at about half the cost of an achromatic oil- 
immersion condenser ; and whilst it can only be employed with a 
Y2-th inch oil-immersion objective in the manner already described, 
yet it gives excellent dark-ground effects with all powers from 
Ygth to ^th inch. 

One defect if defect it can be called is that, in its present 
form, there is no method of controlling the light passed by altering 
the size of the stop. It is just possible means can be devised to 
allow of this being done. 

In my opinion there appears to be room for a reflecting con- 



306 S. C. AKEHURST ON SOME OBSERVATIONS CONCERNING 

denser to be used with high-angled oil-immersion objectives, even 
though the field for its usefulness may be limited. 

1 hope the photographs illustrating this paper will prove of 
sufficient interest to stimulate further investigation into the 
value of annular light, and to demonstrate what limits, if any, 
should be put upon its use. 

Descriptions of Plates. 
Plate 20. 

Figs. 1 to 7 are illustrations of various figures of the spectra 
of Pleurosigma angulatum as seen at the back lens of an oil- 
immersion objective with the diatom in focus an achromatic 
condenser, with and without stop, and reflecting condenser being 
used. Pigs. 1 to 3 are of no special interest just now most of 
you are familiar with these diffraction spectra, varied according 
to the diameter of the opening in the iris diaphragm. 

Fig. 1 shows result obtained with the diaphragm almost closed. 

Fig. 2 the diaphragm is opened so that one-third of the back 
lens is in shadow. The details of the diatom are hardl) T per- 
ceptible, being flooded out by excess of light. 

Fig. 3. The iris is closed, until two-thirds of back lens is in 
shadow. In this position, with the spectra just touching the 
edge of the central beam of light, the best resolution of Pleuro- 
sigma angulatum is obtained. 

Fig. 4 shows the spectra obtained when a large spot is used. 
The six diffraction spectra forming the symmetrical image should, 
however, be slightly moved from the centre outwards to reduce 
the diameter of the hexagonal spot in the centre, which in the 
drawing is a little too large. In this instance insufficient light 
was passed, and an unsatisfactory image of the diatom was dis- 
played. My next spot being too small, the picture of the spectra 
obtained is as shown by flg. 5. Here Ave have six dark cuspidate 
forms, disposed as a six-pointed star, the intermediate spaces 
being filled with a diffused light, the whole figure being some- 



SUB-STAGE ILLUMINATION. 307 

what ill-defined. This effect was due to an excess of light ; by 
slightly closing the iris diaphragm the light was reduced, and we 
have the result as shown in fig. 6 the symmetrical design well 
defined on a black ground, and just a glimpse of another portion 
of the spectra at six points round the shadow caused by the partly 
closed diaphragm. With the spectra showing, as illustrated in 
fig. 6, I obtained the best definition of Phurosiyma angulatum 
with achromatic condenser and spot. 

Fig. 7 is the record of the spectra obtained of the same diatom, 
using the reflecting condenser ; the similarity between the figures 
7 and 5 is noticeable. 

My reflecting condenser to work at its best when using it for 
annular light requires the light cut down until a crisp image is 
shown of the spectra as at fig. 6. 

Fig. 8 represents the rulings on an Abbe test plate, as displayed 
by T V inch oil-immersion objective and reflecting condenser. The 
position of the light bars is to be noted : there are six those at 
the top and bottom are not quite fully displayed. On first 
examining the back of the objective I observed the two rows 
of six white dots, as shown at fig. 9. At another examination 
the light probably being more central I found an almost com- 
plete circle, as at fig. 10, made up of ten white clots on each side 
and a thin streak of light at the bottom. I have not yet been 
able to put forward a suggestion as to how these are formed. 
I have, however, included them in my record, as they may be 
of some interest. 

Plate 21. 

Fig. 1. Nitzschia linearis x 2,500, showing the white-dot image. 
This photograph was taken with a highly corrected oil-immersion 
condenser and axial illumination. 

Fig. 2. Nitzschia linearis x 3,000, this time showing the 
black-dot image. This photograph was taken with reflecting 
concentric condenser. 

Journ. Q. M. C, Series II. No. 74. 22 



308 S. C. AKEHURST ON SUB-STAGE ILLUMINATION. 

Both these pictures were taken by the same man, using the 
same objective, diatom and illumination the only difference 
being in the condenser used. Regarding this matter, Mr. 
O'Donohoe writes as follows : " I was never able to see the 
black-dot image when using my ordinary oil-immersion condenser, 
hence was much surprised to find that the reflecting concentric 
condenser showed the black dots beautifully. This and the 
Amphipleura show that the reflecting condenser is a better re- 
solver than my ordinary oil-immersion condenser and axial 
illumination. 

Fig. 3. Amphipleura pellucida x 2,000. This photograph was 
taken to demonstrate the usefulness of annular light when 
searching a slide for fine structure. The diatoms are at right 
angles to each other, and both resolved. Had light in one 
azimuth been employed, such as one gets with an achromatic 
condenser, and quarter-moon stop, only one would have been 
resolved, viz. the diatom with striae at right angles to the 
direction of the beam of light. 

Fig. 4. A record of Surirella gemma x 2,000. This was 
taken with the reflecting condenser. The black dot is shown, 
and at the same time the ribs are resolved into dots. 

Plate 22. 

Fig. 1. Navicida rkomboides x 1,500, taken with the re- 
flecting condenser. 

Fig. 2. Pinnidaria nobdis x 2,500, showing the costae filled 
with dots. Taken with the reflecting condenser. 



Journ. Quekett Microscopical Club, Scr. 2, Vol. XII., No. 74, April 1914. 



Journ. O.M.C. 



Ser. 2, Vol. XII., PI. 20. 



WEW OF BACK LENS' OP OBJECTIVE 

j < 

PL EURO SIGMA. >- HG\J LATUM I hi FOC 



JCATIC 
CONDENSE ~ 

*fl r 




ACHROMATIC 

C0Ni)NSR 

'.Ml Ttf 

STOP 



CCNCEI 
REFLI 

CONDE.NSER 





A 








u. 






Jk B B e 

TLiT 
PLATE 




C. H. Caffyn, photogr. 



Journ. Q.M.C. 



Ser. 2, Vol. XII., PL 21. 











T. A. O'Donohoe, photogr. 

Resolution with Annular Illumination. 



Journ. Q.M.C. 



Sen 2, Vol. XII., PL 22. 





T. A. O'Donohoe, phologr. 

Resolution with Annular Illumination. 



o 



09 



AN ATTEMPT TO RESOLVE AND PHOTOGRAPH 

PINNULARIA NOB I US. 

By T. A. O'Doxohoe. 

(Read January 21th, 1914.) 

Most microscopists are acquainted with the little diatom called 
Pinnidaria nobilis, which, on the test slides of twenty diatoms 
mounted by Moller and Thum, takes the second lowest place, 
with striae numbering from 11,000 to 12,000 to the inch. 
It is just because it occupies such a lowly place that it is 
passed over with contempt as being worthy of the notice only 
of the babes and sucklings of microscopy who find themselves 
in possession of a 2-inch or 1-inch objective. 

Such was my own feeling towards it until quite recently, 
when Mr. Akehurst showed me by resolution into dots that it 
deserved a better fate, and invited me to resolve and photograph 
it, if I could, and for this purpose he, at the same time, lent 
me a realgar mount and the reflecting dark-ground condenser 
of Leitz. I have since learnt that an objective and illumination 
which, without any manipulation, showed me at once the striae of 
Nitzschia linearis, Frustulia saxonica, and Amphiplewa pellucida, 
and the very distinct black dots of all the other diatoms on 
Thum's test plate of 30 forms, failed completely in inducing the 
Pinnidaria nobilis on the same slide to yield up its secrets. So 
that the diatom to which almost the lowest place is assigned 
by the mounter is, in fact, by far the most difficult to resolve. 
Examined with a drv lens of N.A. - 85 and direct cone of 
light, we get an image in which on each side of the raphe 
are seen two zig-zag lines running from end to end and dividing 
the linger-like bands into three series or each band into three 
compartments. This is all that can be seen with a dry lens. 

Now using a Zeiss 2-mm. apochromat N.A. 1*3, and Watson's 
Holoscopic immersion condenser, and finding a central cone of 
light unavailing, I inserted the crescent stop in the condenser, 
and proceeding as if I were resolving the striae of Amphiphura 
pellucida, I succeeded in getting an image which shows what one 



310 T. a. o'doxohoe on pin nul aria nobilis. 

must call the costae, broken up into three parts, with very fine 
lines between them. It may be seen that the middle parts of 
the costae are in the sharpest focus because they represent the 
highest of three distinct planes. Now if this interpretation be 
correct, the structure of this diatom is very complex, as there 
would be three planes on each side of the raphe, and the planes 
on the one side would coincide with those on the other only when 
the diatom was perfectly flat on the cover-glass a very un- 
likely case. 

I now tried to resolve the costae, with the result as shown 
[here an image was projected on the screen], which reminds one 
of the bones of a skeleton's hand. 

There remained the resolution of the very fine lines between 
the costae, probably into dots. After trying to do this many 
hours without any success I substituted Mr. Akehurst's dark- 
ground condenser for the Holoscopic, with the result that, after 
considerable manipulation I was able to get the photograph here 
reproduced. (See PI. 22, fig. 2.) This shows at least partial 
resolution on both sides of the raphe. 



Journ. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 74, April 1914. 



311 



NOTES. 

ON A METHOD OF MARKING A GIVEN OBJECT FOR 
FUTURE REFERENCE ON A MOUNTED SLIDE. 

By James Burton. 

{Read November 25th, 1913.) 

Most likely all of us at times have come across some particular 
object on a mounted slide which we have felt we should like to be 
able to find on another occasion ; perhaps some special diatom on 
a strewn slide, for instance. Now there are several methods of 
doing this, and a little piece of apparatus is sold by the opticians 
which marks a circle round an object first found under the micro- 
scope. But perhaps with the majority the necessity does not 
occur often enough for it to be worth while to keep a special tool, 
and the little dodge, if I may call it so, which is here described 
can be carried out without any other instrument than those we 
most of us already have and use. If the object to be marked is 
sufficiently large for recognition under a moderate power, such as 
can be obtained with a hand lens or dissecting microscope, the 
matter is very simple. First find the object, then with a fine 
camel-hair or sable brush carefully place a dot of water-colour 
over it large enough to be seen with the naked eye, set it on one 
side to dry ; when dry, put the slide on the turn-table with the 
dot accurately in the centre and turn a small ring round it with 
any dark cement you may have in use; when this is hard, which 
will depend on the kind of cement used, the water-colour can be 
removed with a damp brush, and the cover can be carefully 
cleaned with a piece of soft rag. 

If the object, however, is too small to be readily recognised 
without a high power, as, of course, is usually the case, for 
it is not necessary to mark anything but minute objects, 
a rather more complicated variety of the same plan should 
be adopted. Again first find the object with a suitable 
power, such as a | inch or ^th inch, and let the specimen be as 



312 J. BURTON ON A METHOD OF MARKING A GIVEN OBJECT. 

accurately placed in the centre of the field as possible ; then sub- 
stitute for this power, preferably a water- immersion objective, 
say T V^h, put on the front lens a small drop of water and care- 
fully focus. It is necessary that the slide should not be moved 
after contact is made, as it is desirable to keep the drop of water 
as small as possible. When the object is recognised and is in the 
centre of the field, raise the microscope tube rather sharply and a 
small circular spot of water will be left on the cover-glass right 
over the desired place. Now stain this spot with water-colour as 
in the other case 1 always use the carmine kept for feeding 
infusoria, etc., but any colour will do. When this is dry the 
slide may be roughly examined and the object will be seen 
through the coat of colour, which for this purpose should not be 
too thick. If it be rightly placed, proceed as before, putting a 
fine ring of suitable size round the spot with some dark cement, 
and when this is dry carefully clean off the colour, and the 
arrangement is complete. Water-immersion lenses are not very 
commonly used now, and if the microscopist does not happen to 
possess one, an oil-immersion may be used instead, but obviously 
it must be used with water, not oil ; but this will give a sufficiently 
good image for our purpose, which is merely to recognise the 
specimen for marking, not to examine it. If an oil-immersion be 
not available, any close- working objective, say gth inch or even 
-g-th inch may be used, but it is necessary that the front lens be a 
small one, so that the spot of water placed by it should be as 
local as possible. 

There are, of course, some difficulties ; the chief is, that objects 
mounted in glycerine as mine usually are are somewhat 
liable to move if at all roughly handled, and may work 
out of the circle ; but with balsam or glycerine jelly mounts, or 
even a shallow glycerine one, there is little danger of this. If a 
turn-table is not in the outfit of the experimenter, a sufficiently 
good circle may be drawn by hand, or a line drawn to indicate 
the position, or, as has been suggested, the barrel of a mapping 
pen or similar object may be used. But the first great difficulty 
is always to indicate the exact spot it is desired to mark, particu- 
larly if the object is a very minute one, and that is got over with 
facility by the method indicated. 



M. DRAPER, A LIVE BOX FOR THE OBSERVATION OF INSECTS. 313 

A LIVE BOX FOR THE OBSERVATION OF INSECTS 

AND SIMILAR OBJECTS. 

By B. M. Draper. 

{Read December 23rd, 1 ( J13.) 

This live box, which was worked out for me by Mr. Angus, 
displays satisfactorily, with superstage illumination, under the 
lowest powers, large creatures such as house-flies. It is not 
meant for pond-life. 

It is of the simplest description, being really nothing but a 
transparent chamber of the shape and size of a small pill-box. 
The body is made of a short piecs of glass tube of any size de- 
sired, say, one-third of an inch deep by two-thirds in diameter ; 
this is cemented to a 3 X 1-inch slip. The lid, which is loose, 
is a circular plate of glass of rather larger diameter than the 
body. In the lid, near its circumference, and at equal distances 
from each other, are fixed three short pins, projecting downwards, 
so as to clasp the outside of the body and thus keep the lid in 
position. The little collars by which the pins are fixed in the 
lid rest on the rim of the box, so as to prevent the lid itself 
from touching. The crack thus left gives enough ventilation. 
The depth of the box can be varied by means of a false bottom, 
preferably opaque. 

This box serves well for the exhibition of a fly in the act of 
feeding. If a little syrup is put on the inside of the lid of the 
box, the sucking surface of the proboscis may be seen in action. 



DARK-GROUND ILLUMINATION WITH THE GREEN- 
HOUGH BINOCULAR. 

By B. M. Draper. 

{Bead December 23rd, 1913.) 

The Greenhough pattern of binocular consists, as is well known, 
of two separate microscopes, one for each eye, with paired 
objectives of very low power. Like other binoculars, it is 
particularly well suited for use with dark-ground illumination, 
and a good way of getting the dark ground with its higher 
powers is to put a stop behind the condenser. 



314 B. M. DRAPER ON THE GREENHOUGH BINOCULAR. 

As, however, the front lenses of the twin objectives stand out 
some distance on either side of what would be the optic axis of an 
ordinary microscope, the stop has to be correspondingly broad 
from side to side ; otherwise direct rays would enter the objectives 
and would spoil the dark ground at the sides of the field. But it 
is not necessary that the rectangular diameters of the stop should 
be equally great ; on the contrary, if an ordinary circular stop be 
used, some rays are needlessly obstructed. On trial, a double 
or twin stop, corresponding with the twin objectives, gave much 
better results. This stop consists of two small circular patches 
placed side by side in the same plane, and touching each other r 
so as to form a figure of eight. It is used behind the condenser 
in the same way as an ordinary circular stop, and with almost 
equal ease. It is only necessary to be careful that the two circular 
jDatches shall be placed horizontally, i.e. so as to be opposite the 
two front lenses of the twin objectives. This position can easily 
be secured by arranging the stop in the carrier approximately and 
then, whilst watching the object, shifting the whole condenser 
round in its sleeve until the best effect is obtained. A standard 
low-power condenser such as Swift's " Paragon," with its top lens 
off, gives very satisfactory results. The twin and the ordinary 
circular patterns of stop were compared experimentally by using a 
condenser fitted with two stop carriers, one behind the other, so 
that either stop could be used separately, or both together. The 
twin stop used by itself gave a good dark ground. The circular 
stop was purposely chosen too small to give a good dark ground ; 
there was light at the sides of the field. Nevertheless when the 
circular stop was turned in above the twin stop whilst the object 
was under observation, there was a marked drop in the brightness 
of the image. This loss of light was due almost entirely to the 
circular stop, not to the clear white glass on which it was mounted, 
since it was found that the interposition of such a. piece of glass,, 
even when rather dirty, made very little difference to the light. 
Evidently, therefore, the circular stop, though too small in one 
direction, was too large in the other, and kept out some rays 
which might safely have been admitted. Of course if the circular 
stop had been large enough to darken the background when 
used by itself, the loss of light would have been still more 
noticeable. 



E. M. NELSON ON AMPHIPLEURA LINDHEIMERI. 315 

AMPHIPLEURA LINDHEIMERI. 

By Edward M. Nelson, F.R.M.S. 

(itearf December 23rd, 1913.) 

Half a century ago Xavicula rhomboides was the accredited test 
for the best microscope lenses. This was the common " English " 
rhomboides, which has about 72,000 to 73,000 striae per inch ; it 
was also known as the Amician test. About the seventies 
iV. rhomboides was discovered in America. This was a coarser 
form, having some 60,000 striae per inch, consequently any 90 
| inch N.A. 0*71 would resolve it readily. In those days there 
were no cheap apertometers to be had, so testing an objective 
merely meant a measurement of aperture by resolving striae 
on some diatom by means of oblique light in one azimuth. We 
now know that the feat can be accomplished by a very badly 
corrected objective. 

The new coarse American rhomboides became very popular, and 
diatom dotters and brassey glassites simply revelled in it. 

History has, however, repeated itself, for as time went on lenses 
improved, and both the coarse and fine rhomboides failed as tests 
for high powers, so others had to be found to fill their place. 
Amphipleura pellucida became the test for immersions, while 
A. Lindheimeri was used for dry lenses. As A. Lindheimeri has 
about 7 ",000 striae per inch, it is a very suitable test, with oblique 
light from a dry condenser, for lenses of the 7a type. 

This w T as the favourite test of the late Lewis Wright, who 
mentions it in his excellent book on the Microscope. But now 
another Lindheimeri has been discovered in Spain, and as it is a 
coarser variety, it is necessary to distinguish between these forms 
when quoting the Lindheimeri as a test. The new Lindheimeri 
has 67,000 striae per inch, and therefoi e is easier to resolve than 
the old English rhomboides ; a | inch, or 8 mm., will very nearly 
resolve it in fact, they do so in patches; a Powell 100 | inch 
of 1S75, which would fail on an English rhomboides, resolves it 
easily. 

The new Lindheimeri can be recognised at once by its very long 
terminal nodules, the terminal nodule being one-third of the whole 
length of the valve, while in the old form it is only one-fifth. 



316 E. M. NELSON ON AMPHIPLEURA LINDHEIMERI. 

The length-breadth ratio in the new form is 7*5, and in the 
old 8-5. 

The conditions here are therefore opposite to those we found in 
Naviada rhomboides,* for those with the greater ratio had the 
coarser striae, but in this case they have the finer. 

If we divide the ratio by the number of striae in T ff ^th of an 
inch we shall obtain a numerical index of about 1*1. Thus : 

Old Lindheimeri : Ratio 8*5, striae 7*7, index l'l. 

New Lindheimeri : Ratio 7 '5, striae 6*7, index l'l 2. 

Amphipleura pellmida follows much the same rule,for "resolvers" 
who understood the subject sought out wide valves, i.e. those with 
a small ratio. 

* Journal Q.M.C., vol. xi. p. 97, 1910. 



Jovrn. Qv.ekclt Microscopical Club, Ser. 2, Vol. XII., No. 74, April 11)14 



317 



SOME NOTES ON THE STRUCTURE OF DIATOMS. 

By N. E. Brown, A.L.S. 
(Read March 2ith, 1914.) 

Plate 23. 

These notes are offered to the Quekett Microscopical Club, not 
-with the anticipation that, with the exception of one point, the 
-expert will find in them much that is not already known, but 
because my interpretation of certain familiar features is different 
from that which is usually accepted and may therefore be of 
some interest in promoting thought in another direction. 

Structure of Pirmuiaria spp. Although P. major and allied 
species are familiar to all microscopists and their structure is 
doubtless well understood by experts, yet the description of it in 
English text-books is by no means satisfactory and also does not 
seem to be too well known. A good description with figures by 
Floegel will, however, be found in the Journal of the Royal Micro- 
scopical Society, 1884, vol. 4, p. 509, t. 8 (Pinnularia). 

I regard P. major as a very simple type, perhaps one of the 
simplest types of diatom-structure. In front view the valve pre- 
sents a series of transverse markings on each side of the raphe, 
which are so easily seen that I believe few diatom- dotters pay much 
attention to them. These markings consist of linear cavities or 
canals in the valve, separated from one another by very thin par- 
titions, and each of them is provided with a comparatively large 
linear-oblong opening on the inner side, communicating with the 
interior of the diatom ; it is evident that during life the protoplasm 
enters and fills these cavities, and therefore they must play an 
important part in the life-economy of the diatom. The motions of 
n living diatom are not only interesting to watch, but are puzzling 
to everv one who has observed them. It is no uncommon thing to 
see a Pinnularia or other free-swimming diatom apparently take 
hold of a particle of dirt and move it to and fro along its sides or 
upper surface. On one occasion I saw P. major with two frag- 
ments of dirt, one on each side of it near the margin ; both pieces 
"were moved forwards and backwards in the same direction for 
-a time and then suddenly they were moved each in a different 



318 N. E. BROWN ON THE STRUCTURE OF DIATOMS. 

direction, and finally one piece was passed from one side completely 
round one end to the other side, where, upon meeting the other 
piece of dirt which was moved towards it, the invisible hands 
moving the dirt lifted it up and placed it upon the other piece of 
dirt and held it there, both together being then moved up and 
down as before. Now this and other movements I have witnessed 
could only have been made at the will of the diatom, and in my 
opinion must have been controlled by living matter extruded from 
the interior of the shell, and therefore there must be openings 
through which the interior is in communication with the exterior 
other than at the raphe, where, as is well known, a crest of proto- 
plasm extrudes, which, from measurements I have made, varies 
from l/14,000th to l/3,000th inch in depth and l/6,000th to 
1/1. 800th inch in breadth. Feeling convinced of this, I sought 
for several years for evidence of pores in Pinnularia without 
finding the slightest trace of them, and all authors I have con- 
sulted state that there are no openings in the valve of Pinnularia 
other than at the raphe. With respect to diatoms in general,, 
in the 8th edition of The Microscope and its Revelations (1901), 
p. 590, it is stated, " We have in fact no positive demonstration 
of the existence of special apertures communicating between the 
outside and inside of the cell." 

However, some four years ago I obtained a sample of the 
Chei-ryfield diatomaceous deposit, and upon mounting some of it 
in picric piperine, found that it contained four or five species of 
Pinnularia, on one of which I at last saw indications of the pores. 
I had so long sought. This species is one of the smallest in the 
material and the only one on which I have been able to see any 
indication of pores. They are only to be seen when the outer 
surface of the cavities is accurately in focus and the light central, 
and are so minute and crowded that they appear like a single 
dusky beaded line extending all the way along the centre of the 
cavity, and they do not appear to be present at any other part. At 
any focal plane below the external surface, such as when the large 
opening into the interior of the diatom is in view, they cannot be 
seen. When viewed from the inside of the valve they are scarcely 
visible except where seen through the large opening of the cavity 
into the interior. Although a distinct bead-like appearance is just 
discernible, the pores are so closely placed that neither I nor the- 
friends to whom I have shown them, have been able to see them 



N. E. BROWN ON THE STRUCTURE OF DIATOMS. 319 

as distinctly separate dots. It is only on this particular species, 
the name of which I do not know, that I have been able to discern 
these pores. Upon the far larger P. major and P. nobilis I can- 
not see any trace of them, although I do not doubt that they 
exist in these species also, but are probably smaller than in the 
species in which I discovered them. As seen by myself and 
friends at a magnification of 3, COO diameters they are as repre- 
sented at PI. 23, fig. 13. 

Upon the sides or girdle of all species of Pinnularia are to be 
seen two slender lines, which under sufficient magnification are 
seen to be composed of a multitude of short transverse lines ; in 
P. major these average about 60,000 to the inch. These lines I 
have failed to resolve into distinct dots, although Mr. E. M. 
Nelson (Journ. Q.M.C., Ser. 2, Vol. VI. p. 144) states that he 
has done so, and I do not doubt his statement. But at the same 
time I very much doubt if the clots of which these transverse 
lines are composed are real pores. The lines are so easily seen 
that they evidently are much too coarse for pore structure, and 
my interpretation of the structure of these two lines on the 
girdle of Pinnularia is, that each line consists of a multitude 
of very minute cavities placed side by side, similar to those seen 
in the front view of the valve, and that when they are truly 
resolved each cavity will be found to have a minute pore at the 
centre or a row of pores along the central line of each cavity or 
clear space between every pair of short transverse lines. 

It may be well to state that there are sometimes appearances 
to be seen on the walls of the cavities of P. major and P. ?iobilis 
which may easily be mistaken for rows of pores. As I have 
seen them, they appear like two rows along each cavity, but 
upon moving the mirror slightly these rows move also, and 
clearly demonstrate that they are only diffraction images. 
The true pores of these species, when discovered, will, I believe, 
be in one central row. 

Pleurosigma balticuni. In a paper recently published in the 
Journ. Q.M. 6'., Ser. 2, Vol. XII. p. 155, Mr. T. O'Donohoe has given 
an account, accompanied by some excellent photographs, of certain 
details of structure of this diatom as seen in a strewn slide 
mounted in realgar belonging to Mr. B. J. Capell. By the 
courtesy and kindness of Mr. Capell I have also had the privilege 
of examining this slide, and am fortunate enough to be able to 



320 N. E. BROWN ON THE STRUCTURE OF DIATOMS. 

add something concerning the structure to be seen on it that 
appears to have escaped the eyes of Mr. O'Donohoe. 

In the process of melting the realgar, either the great heat 
required, or some chemical action set up by it, has acted upon 
some specimens of P. balticum and completely dissolved part 
of the shell, leaving only film-like strips flattened upon the 
cover-glass, whilst others have been quite unaffected. One 
specimen shows in a very clear manner the dissolving action in 
progress, but arrested at the moment when a subcentral part 
of the diatom had become fused into a structureless strand of 
silica, connecting the two ends, which remain intact. These 
films above mentioned, which Mr. O'Donohoe has photographed, 
will prove, I think, to have an important bearing upon our 
more complete understanding of diatom structure. 

If the outer surface of a perfect valve of P. balticum be 
examined under a binocular, it will be seen that the sides curve 
away from the raphe very much as the sides curve away from 
the keel of a boat when turned bottom upwards, so that the 
surface is nearly always oblique to the surface of the cover- 
glass. From this cause I have found the structure of a perfect 
specimen extremely difficult to understand, as a very slight 
modification of the illumination or alteration of focus under high 
powers, or the two combined, produce a number of different 
appearances six or seven have been noticed all apparently 
demonstrating true structure, so that it is practically impossible 
to form an opinion as to which view, or views, represent the real 
structure of the valve. Owing to this, I suppose, has arisen the 
diverse views held of the structure by different authors. 0. Miiller, 
for instance, in" the Deutschen Botanischen Gesellschaft for 1898, 
Vol. XVI. p. 387, t. 26, fig. 8, regards the pores (by which 
I understand he means the black dots) in the cell- wall as 
perforations passing completely through the wall, which are 
not perfectly tubular, but enlarged at their centre and contracted 
to a minute opening on the internal and external surface of the 
valve thus : 




porej 

Mr. T. F. Smith, however, in the Journ. Q. M. C, Ser. 2, 



N. E. BROWN ON THE STRUCTURE OF DIATOMS. 321 

Vol. III. p. 306, regards the valve as "composed of two layers 
of grating"; whilst Mr. E. M. Nelson in the Journ. Q.M.C., 
Ser. 2, Vol. XII. p. 99, fig. 4, states that " in P. balticum 
and allied forms the upper membrane has slit-like apertures in 
longitudinal rows, while the lower membrane has circular 
apertures (fig. 4), where the circular apertures in the lower 
membrane are seen through the intercostal silex of the upper 
membrane and in a line between the slits." Finally we have 
Mr. O'Donohoe's interpretation referred to above. 

Until August 1913 I held the view (which I think is the 
prevailing one) that the black dots visible on the valve of a 
diatom were pores or perforations passing completely through 
its substance, and that the white-dot view was an out-of-focus 
one. Now, however, the examination of Mr. Capell's slide has 
demonstrated to me and to others who have examined it with 
me, conclusively and beyond any room for doubt, that many 
(possibly all) of the black dots that are ordinarily seen on a- 
diatom are not pores at all, or at the most are only pits con- 
taining the pore-bearing membrane, and that the white-dot view 
is often much more correct for seeing what I believe to be the 
true pore-structure than has been supposed. 

I have long been puzzled at the behaviour of black dots under 
high magnification, and have therefore suspected that they 
were not quite what they seemed to be for some time past, but 
I think the evidence of Mr. Capell's slide fully explains their 
nature. 

In any perfect valve of P. balticum it is easy to obtain a view 
of a grating-like structure with square meshes, formed of bars- 
or rods of silex crossing one another at right angles. In the 
partly dissolved films on Mr. Capell's slide this grating is not 
evident, but instead the films are seen to consist of parallel 
dark rods having a beaded appearance, held in place by a 
membrane of silex (see Mr. O'Donohoe's figures, op. cit., t. 14 r 
figs. 3 and 4). At the ends or other parts the rods are seen 
to project in a ragged manner. These rods are those which lie 
parallel to the raphe in the perfect grating, while those which 
in the perfect diatom form the transverse bars of the grating 
structure have been dissolved, leaving no trace, or only a very 
faint one, visible. When examined with an oil-immersion objective 
at a magnification of 2,000 to 3,000 diameters these bars are 



322 N. E. BROWN ON THE STRUCTURE OF DIATOMS. 

seen to be thickened in a beaded manner at short equal intervals. 
Tn some cases a few of these rods are curved away from the 
surface of the valve, and one of them in such manner that part 
is seen in surface view and part seen in side view, and traceable 
from one view to the other (see Mr. O'Donohoe's photograph, 
op. cit., t. 14, fig. 2. where it or a similar rod is shown out of 
focus). Now it is obvious that the bead-like swellings occur at 
the points where, in the perfect grating, the transverse bars 
crossed and were fused with those parallel to the raphe, and 
that these transverse bars were either more easily dissolved or 
lie at a slightly lower level than the longitudinal bars, and so 
are more quickly attacked by the dissolving action. In all cases 
the films are very closely appliel to the cover-glass, indicating 
that its cooler surface has in some way retarded the dissolving 
process, so that the parts of the diatom farthest from the cover - 
glass were always dissolved first. That the longitudinal bars over- 
lie the transverse bars seems to be probably the correct view, as 
under certain conditions of illumination the longitudinal bars seem 
to pass over the transverse ones, and is supported by the testimony 
of the curved bar mentioned above as seen in side view. At 
a magnification of 3,000 diameters it is clearly seen that the 
edge of the bar facing the outside of the diatom is perfectly 
even, while the edge facing the interior projects into little hemi- 
spheres at the points where (in surface view) it is bead-like (fig. 2). 
Also at the marginal part of the valve, where the longitudinal 
bars are normally undeveloped and only the transverse bars 
are evident, these latter become pressed nearer to the cover- 
glass, and are not dissolved. 

The bars can be distinctly seen to be solid pieces of silex, which 
go to form the strengthening grating and support the membrane 
which covers the exterior of the diatom. At a certain focus the 
beads or nodes at the crossing of the bars, owin2f to refraction 
or diffraction, assume the appearance of black dots so familiar to 
all microscopists, demonstrating conclusively that these black 
dots are not pores, but shadows produced by some refractive 
or diffractive property of the nodes of the grating-bars. 

From the movements T have seen diatoms perform it is evident 
they must have some means of communication through the valves 
with their surroundings, and finding that the black dots on this 
diatom are certainly not pores, I sought for them in the membrane 



X. E. BROWN OX THE STRUCTURE OF DIATOMS. 323 

covering the meshes of the grating. This membrane is extremely- 
thin, probably not thicker than the film of a soap-bubble, and 
is raised into a slight dome or convexity over each mesh of the 
grating. When the apex of these convexities is accurately in 
focus, and the headings of the bars seen as black dots forming 
squares, the light being central and with a magnification of 
2,000 to 3,000 diameters, a very minute dot is seen at the 
centre of each square (PI. 2, fig. 1). This central spot I conceive 
to be a true pore through the membrane ; it is very minute, at 
the most not more than one-third of the diameter of the black 
dots themselves, and is probably not more than 1/200, 000th of an 
inch in diameter. It is not quite easy to see, but can be made 
clearer by the use of a small central stop in the substage con- 
denser. I doubt if it can be seen at all at a less magnification 
than 1,000 diameters; and with a dry Zeiss y-th, at a magnification 
of 3,000 diameters, I do not feel quite sure that I see the pores. 
There seems a suggestion of their presence, but I do not think 
any dry lens will show them very clearly. Under dark-ground 
illumination, with a Leitz dark-ground illuminator, the bars 
are white and the headings on them appear much larger than 
when seen by direct light, whilst the membrane is not seen at 
all, the spaces between the bars being black. But if the funnel- 
stop which cuts down the aperture of the lens is removed, the 
illumination remaining as before, then the bars appear to be 
very slender and black and the membrane whitish, with the 
minute pores clear and distinct. 

Upon entire specimens of the diatom the pores are difficult to 
see, apparently owing to the convex curvature of the shell, but 
with a little trouble I have been able to see them in places upon 
every specimen examined. Under certain conditions of illumina- 
tion a small dark spot, which might easily be mistaken for the 
pore, is seen at the centre of each of the beads of the membrane ; 
this spot, however, is very much larger than the true pore, 
and appears to be some diffraction image, possibly that of the stop 
in the condenser, as can easily be demonstrated by moving the 
mirror slightly, when the spot is seen to shift its position. 

Although all to whom I have shown these pores agree with me 
that they are very minute, yet they appear to have a different 
size to different observers. To my eye they appear to have about 
the proportion to the black dots I have represented in my drawing, 

Journ. Q. M. C, Series II. No. 74. 23 



324 N. E. BROWN ON THE STRUCTURE OF DIATOMS. N 

to others the} 7 evidently seem larger, as one friend said he thought 
that about five of them just touching one another would extend 
right across one of the meshes of P. balticum, but even at that 
rate they would not be more than 1/1 80,000th of an inch in dia- 
meter, whilst I think they cannot be more than l/200,000th 
of an inch in size. 

With regard to Mr. Smith's statement that there is a second 
grating, I have not the slightest doubt that the transverse bars 
form such a grating, but I have not seen it separately from the 
outer grating. In Knowledge for 1911, p. 334, Mr. Smith 
reproduces a photograph of P. balticum in which the longi- 
tudinal strengthening bars are shown and are there called 
" fibrils," a term which Mr. O'Donohoe has also adopted, but 
which to me seems wholly inapplicable, as they appear to me to be 
supporting structures for the delicate membrane and in no sense 
ultimate structures. It may not be out of place here to point 
out that the membrane I speak of and illustrate is a totally 
different thing from that which Mr. Smith in the Joum. Q. M. 0. f 
Ser. 2, vol. 3, p. 301, t. 3, fig. 5, and in Knowledge (1911), pp. 289- 
93, and 221-35, and (1912) p. 371 describes and figures as a 
"delicate membrane' 3 and "torn structure." For it is a 
matter of great surprise to me that Mr. Smith did not recognise 
that this supposed "delicate membrane " and "torn structure" 
has no morphological connection with the diatom. I had sup- 
posed, previous to reading his paper, that every one regarded 
this appearance merely as an incrustation cementing the diatom 
to the cover-glass ; it is of very common occurrence upon 
Pleurosigma and some other diatoms. I have always regarded 
it as due to the exudation of a residual salt, which, after 
boiling in acid, has not been thoroughly washed out of the diatom 
(and it is indeed very difficult to wash out completely), so that 
when mounting them on a cover-glass the water outside the 
diatom evaporates first and the salt then gradually percolates out 
through the pores of the diatom, and, in drying, fixes it to the 
cover-glass, and being of low refractive index produces the 
appearance we so often see. 

It will be noted that there is a discrepancy between my 
drawings and Mr. O'Donohoe's photographs in the size of the 
black dots, for although mine are represented at a greater 
magnification, they are smaJler than in the photograph. This is. 



X. E. BROWN ON THE STRUCTURE OF DIATOMS. 325 

probably because the photographs were taken at a focus where 
the membrane is not visible and where diffraction effects are at a 
maximum, whilst at the focus of the surface of the membrane 
they are reduced to a minimum. 

Since writing the above I have had the advantage of being able 
to examine a realgar mount of P. balticum belonging to Mr. E. 
M. Nelson. The realgar of this slide is not nearly so clear and 
brilliant as that of Mr. CapelTs slide, and on some parts of it I 
cannot see the pores in the films at all, but there are some films 
where they can be most distinctly seen. I mention this, because 
others possessing realgar mounts of this diatom might fail to find 
the pores on some of the films and believe them not to be present ; 
they may be extremely difficult to make out, or quite invisible on 
parts of the valve where both longitudinal and transverse grating 
or strengthening bars are present. 

Pleurosigma angulatum. Upon Mr. Oapell's realgar slide 
are also numerous specimens of this diatom ; some are bent or 
contorted, but otherwise, with the exception of two or three 
specimens, seem unaffected by the heat or dissolving action. 
One of these exceptions, however, is an exceedingly interesting 
specimen, and clearly confirms Mr. E. M. Nelson's statement in 
the Journ. Q. M. C, Ser. 2, Vol. XII. pp. 98-100, that the valve 
of this diatom is composed of two gratings. It is a single valve 
and therefore its structure is not obscured by images from the 
opposing valve, is fractured in places, and has its outer surface 
next the cover-glass, as can be verified by examination under a 
binocular. Over a small area some solvent has caused a portion 
of the outer grating to peel off, and at one place a small patch of 
it is seen adhering to the cover-glass ; this patch is represented at 
fig. 5, as seen when magnified 3,000 diameters. At this magnifi- 
cation the bars of silex forming the boundaries of the meshes are 
seen to cross one another diagonally, forming diamond-shaped 
meshes, and are thickened at the nodes or points of intersection 
just as in P. balticum, and, as in that diatom, it is these nodes 
which produce the black-dot appearance. At the centre of 
the membrane covering each mesh a very minute pore can be 
seen when the surface of the membrane is accurately in focus. 
These pores do not seem to be visible under direct central light 
without the interposition of a stop in the condenser, and I find 
that they are best seen when illuminated by means of a Leitz 



326 N. E. BROWN ON THE STRUCTURE OF DIATOMS. 

dark-ground illuminator, but without using a funnel-stop in the 
lens. Under this method of illumination they are remarkably 
clear and distinct, and the membrane itself appears to be slightly 
concave as viewed from the outside of the valve. At one focus 
and under slightly oblique illumination, one set of bars appears to 
cross over the other set, as I have represented diagrammatically at 
fig. 6 ; at this focus the pores are invisible. Upon the specimen 
from which the fragment is separated both the outer and inner 
gratings are seen to be composed of hexagonal meshes, as at 
figs. 7 and 8, and I find it very difficult to get a view of the 
diamond-shaped meshes on the entire part of this particular 
specimen, although upon other specimens I have been able to see 
them and the pores very clearly and easily, as well as the under- 
lying hexagonal meshes. It would seem as if the outer grating 
may really be a double structure, with a film of diamond-shaped 
meshes overlying others that are hexagonal. 

Under certain conditions of illumination a third set of bars can 
be seen on entire specimens, crossing the diagonals at right angles 
to the raphe, but I have failed to see any trace of them on the 
separated fragment represented at fig. 5, so that I think it very 
probable that they have been dissolved away from that piece, 
just as also appears to have been the case in the films of 
P. balticum. For I think there can be no doubt that some such 
bars exist, because at one focus, under varying conditions of 
illumination, the gratings appear to be composed of nearly square 
meshes as represented at fig. 9. At a very slight alteration of 
focus this appearance alters to the hexagonal one as represented at 
figs. 7 and 8, which I take to be that of the exact focal plane of 
the membrane covering the meshes of that particular grating. 
When the inner grating is examined where the outer grating is 
stripped off, looking upon it from the outside of the valve, it first 
presents the appearance of a solid plate of white silex with dark 
hexagonal perforations in it. At a slightly lower focus this gives 
place to hexagonal meshes with dark boundaries and the mesh 
covered with a clear membrane having a pore at its centre ; this 
latter I look upon as being the true image of the inner grating 
and the above-mentioned appearance of a white plate with dark 
perforations as an out-of-focus image produced by some refractive 
or diffractive property of the membrane, which in some way 
produces over each mesh a hexagonal shadow. Below the focus 



N. E. BROWN ON THE STRUCTURE OF DIATOMS. 327 

of the hexagonal meshes I can sometimes make out a diamond- 
shaped arrangement of dark dots as seen in fig. 5.* 

In this species, as in P. balticum, wherever a junction of two 
or more bars of a grating occurs, there a black dot is seen, due to 
diffraction or refraction of the node so formed. And in my 
opinion wherever grating structure occurs, the nodes may be 
expected to appear as black dots. 

At one place a fragment of the valve is broken off and turned 
edgeways to the cover-glass. This edge-view shows the two 
gratings distinctly, but at the same time, owing to the shadow of 
the mass, I am quite unable to see how they are connected to each 
other. But from an examination of this piece, as well as of the 
valve where the outer grating is stripped off, it is evident that 
the faint brown colour peculiar to this diatom resides in the outer 
grating, the inner one being colourless. 

I cannot, however, confirm Mr. Nelson's statement (Journ. 
Q. M. C, Ser. 2, Vol. XII. p. 99) that the meshes of the outer 
and inner grating alternate with one another, for in this particu- 
lar specimen I think there can be no question that the meshes of 
the outer grating are exactly superposed over those of the inner 
grating when seen with exactly central light. I have tested them 
several times by the unaided eye and by means of a micrometer 
in the eye-piece, and always found them to correspond, except 
when the light was not absolutely central. Also the edge- view 
confirms their superposition so far as I have been able to make it 
out, but it is very difficult to get a really good focal image of this 
part. 

P. angulation has one very obvious peculiarity which I do not 
remember to have seen mentioned, namely, that at the ends of the 
valve the grating suddenly changes from the hexagonal to the 
square type of mesh. This should form a good specific character. 

Surirella gemma. Mixed with Phurosigma balticum on Mr. 
Capell's slide are numerous specimens of Surirella gemma, which, 

* Mr. T. F. Smith is of opinion that the outer grating is different in 
structure from the inner grating, and views of both gratings are given in 
The, Microscope and its Revelations, 8th ed. p. 593, pi. 1, figs. 1 and 2. I 
am not able to confirm this view, for every structural image seen on the 
outer grating I have also"been able to see on the inner grating it is merely 
a question of focus and illumination. The "delicate membrane" on the 
outside of the shell described by Mr. Smith I have already noted under 
P. balticum, so need not make any further remark upon it. 



328 N. E. BROWN ON THE STRUCTURE OF DIATOMS. 

in consequence of having seen the minute pores in P. balticum, I 
eagerly examined, as I was reminded that some four years ago 
whilst examining S. gemma mounted in styrax with a Leitz 
-jL.th achromatic oil-immersion objective of 1*3 N.A. I had seen 
similar pores or dots on the white beads of that diatom. At the 
time, being very busy with other work and thoroughly accepting 
the opinion that the black dots usually seen were pores, I paid no 
attention to what I then saw. Now, however, I examined them 
with fresh interest and found that in this realgar mount the pores 
are distinctly visible. To see them, the valve must be resolved 
into a grating formed of slender, slightly zigzag black bars, with 
the interspaces divided by very slender transverse partitions into 
small meshes (the so-called white-dot focus). At a magnification 
of from 1,800 to 3,000 diameters on some specimens, but not all, a 
minute dark speck or pore at the centre of every one of the 
meshes is very clearly visible (figs. 3 and 4) ; at the same time 
it is so minute that it requires good eyesight to perceive it, 
but, as in other cases, becomes accentuated if a small stop be 
placed in the carrier of the condenser. There is therefore no very 
great difference in the ultimate structure of this Surirella and of 
Pleurosigma balticum, except that in the latter it is the bars 
parallel to the longer axis of the diatom which are most evident, 
whilst in Surirella gemma the bars transverse to that axis are the 
most apparent. It must be understood that I refer here only to 
the fine secondary bars or those of the cell-wall, not to the stout 
primary bars which form the framework of the diatom and sup- 
port the cell- wall. The nodes, formed by the junction of the 
slender partitions with the bars, at another focus produce the ap- 
pearance of black dots by refraction or diffraction as they do in 
Pleurosigma balticum. One specimen of S. gemma on the slide is 
crumpled up and the bars bent and turned aside so as to show 
their nature very clearly when sufficiently magnified, and demon- 
strate that they are exactly of the same character as those of 
Pleurosigma balticum that is, they are the strengthening bars of 
the membrane of the diatom. I have been unable to determine 
whether there is also a membrane over the inner surface of these 
bars, but think it very probable, in which case the white bead- 
like appearance will be chambers with minute orifices in their 
iuner and outer wall. 

This diatom seems to provide the microscopist with a series of 



N. E. BROWN ON THE STRUCTURE OF DIATOMS. 329 

tests ; with lenses having a smaller aperture than about 68 N. A. 
only the primary bars of the framework are visible ; with lenses 
of a larger aperture, the secondary bars (i.e. those of the cell- wall) 
become manifest as very fine lines between the primary bars; 
finally with lenses of large aperture and at a magnification of not 
less than 1,800 diameters these fine lines or bars are seen to b9 
connected by finer transverse bars so as to form a ladder-like 
structure, with a minute pore at the centre of each bead-like 
space formed by the cross bars, or at another focus the bars can 
be resolved into the appearance of rows of dots. 

Navicula serians. The structure of the valve of this species 
seems rather difficult to understand. When I first examined it 
in search of pores, I found it had a rather coarse grating, with 
oblong meshes arranged in six to seven rows on each side of the 
raphe, the longer diameter of the meshes being transverse to the 
latter. These meshes are closed by a very thin membrane of 
silex, at the centre of which can be seen, at a magnification of 
3,000 diameters, a minute dark dot, as represented at the upper 
part of fig. 10. This clot I take to be a pore. With central 
light only a very faint indication of it is seen ; but when a small 
central stop is placed in the condenser it becomes clearly visible. 
This structure is all that I at first noted. But having re- 
examined this diatom with great care under all conditions of 
illumination at my command, I have detected structure which had 
previously entirely escaped my notica. For I find that if the 
outer surface of the valve is illuminated by a Leitz dark-ground 
illuminator and examined at a magnification of not less than 
2,000 diameters, without reducing the N.A. by using a funnel- 
stop, a second grating exterior to and superposed ^upon that 
above described can be distinctly seen. This outer grating is 
evidently extremely transparent and practically invisible by 
central light, so that it very easily escapes notice. I have found 
that the easiest way to make it evident is, first to get [the mem- 
brane of the coarse meshes in focus, as represented at the upper 
part of fig. 10, then gradually but very slightly raise the lens 
above that focal plane, until two dark dots appear over each 
mesh. If these dots are very accurately focused and the dark- 
ground illuminator manipulated so as to illuminate the diatom 
with light reflected upon it from the under surface of the cover- 
glass, the surface of the valve will be found to have the 'appear- 



330 N. E. BROWN ON THE STRUCTURE OF DIATOMS. 

ance I have tried to represent at the lower part of fig. 10. I 
believe that each of these dots, or minute meshes as they really 
are, is closed by an extremely thin membrane of silex, as on one 
occasion, when using a dim light reflected from the cover-glass 
upon the diatom, the presence of such a membrane seemed to be 
very distinctly evident by the light reflected from its surface over 
each dark spot and nowhere else. But I entirely failed to see 
the slightest trace of a pore in it, although I think it probable 
that one exists in each mesh. 

Nitzschia scalaris. When the fine striae on this diatom are 
magnified up to 3,000 diameters, they are seen to consist of 
small beads or pearl-like dots of silex, which are either black or 
white according to illumination. Upon the very thin membrane 
between each pair of these rows of beads, a row of very minute 
pores is just discernible, as represented at fig. 11, which is 
drawn with a camera-lucida, using central light and a green 
screen. Under the best of circumstances they are exceedingly 
faint, and I am not at all sure that they are accurately spaced 
in my drawing, as I found it exceedingly difficult to plot them on 
paper by means of a camera-lucida ; but the drawing is suffi- 
ciently accurate to show their position. It requires good eyesight 
to see them at all, and I do not think they would be visible at a 
less magnification than 2,500 diameters. The light must be 
most carefully manipulated, and for my vision I have found 
them to be most evident in a rather dim light, a glare effaces 
them ; also at a very slight touch of the fine adjustment they 
instantly vanish. As a test for high powers, manipulative skill 
and keenness of vision, I think few things can be found more 
suitable than the resolution of the pores of this diatom when 
mounted in styrax. 

Amphipleura Lindheimeri. When the surface of this 
diatom is accurately in focus (not the black-dot view), a fine 
grating with square meshes is seen, which somewhat resembles 
that of Surirella gemma ; the bars transverse to the raphe being 
straight, whilst those parallel to the raphe form sinuous lines, 
because the ends of the short partitions which divide the space 
between each pair of transverse bars into square meshes do not 
exactly coincide with the ends of the partitions between the 
adjoining pairs of transverse bars. At a magnification of 3,000 
diameters, when the membrane covering the meshes of the 



N. E. BROWN ON THE STRUCTURE OF DIATOMS. 331 

grating shows a somewhat bead-like appearance, a very minute 
dusky dot, which I take to be a pore, is just discernible in the 
centre of every one of them, as represented in fig. 12. These 
pores, I think, are smaller even than those of Sarirella gemma, 
and are very difficult to see, unless perhaps to younger eyes, as 
I judge them to be about the limit of my vision. At a slightly 
lower focus the nodes formed by the junctions of the transverse 
and longitudinal bars assume the well-known black-dot appear- 
ance, and all trace of the other structure disappears. Doubtless 
the structure of A. pellucida is similar. 

Coscinodiscus heliozoides. I have nothing to remark 
upon the structure of the diatom to which Mr. Siddall recently 
gave the above name; but I should like to call the attention of 
experts to its remarkable similarity to Stepkanodiscus Hantz- 
schianus. I have not been able to compare the two, but feel 
sure that C. heliozoides belongs to the genus Stephanodisats, 
and have a suspicion that it and S. Ilantzschianus are one 
and the same diatom. A good figure of the latter will be found 
in the Deutschen Boianischen GesellscJiaft, 1S97, vol. 15, t. 25, 
h> 1 

Stauroneis phoenicenteron. When examined at a magni- 
fication of a few hundred diameters, the valve of this diatom is 
seen to be prettily marked with black dots ; but when magnified 
2,000 to 3,000 diameters and very accurately focused, the black 
dots are seen to be optical effects produced by the membrane 
closing the meshes of the grating. This membrane is slightly 
sunk below the general level of the surface of the grating so as 
to form shallow pits. When viewed with the light quite central, 
without a stop, the bars of the grating appear very much stouter 
and the meshes smaller and not so well defined as they do by 
other methods of illumination, and I have quite failed to detect 
any trace of pores in the membrane by this method. But when 
oblique illumination is used, either by means of Powell & Lea- 
land's chromatic immersion condenser or by a Leitz dark-ground 
illuminator, in such a manner that it is reflected from the under 
surface of the cover-glass upon the diatom, then a pore in the 
centre of the membrane of each mesh or pit is distinctly per- 
ceptible, and the structure has the appearance represented at 
fig. 14, which is drawn by means of a camera-lucida from a 
portion of the grating adjoining the " stauros," at a magnification 



332 N. E. BROWN ON THE STRUCTURE OF DIATOMS. 

of 3,000 diameters. The pores are best seen when the light is 
not very brilliant. 

Triceratium favus. The structure of this diatom, as well 
as that of several other species, has been described and illustrated 
in a very interesting article by Floegel in the Journal of the 
Royal Microscopical Society, 1884, vol. 4, p. 665, t. 9, figs. 21 and 
22, and by Otto Miiller in the Deutschen Botanischen Gesellschaft, 
1898, vol. 16, p. 387, t, 26, fig. 5, and 1899, vol. 17, p. 435, t. 29, 
figs. 1 to 5. Both these authors figure and describe the valve 
as consisting of honeycomb-like hexagonal chambers, which are 
open at the outer surface and closed by a very thin perforated 
plate at the inner surface of the shell. Floegel made sections of 
the valve, and from his drawings of what he saw one would 
expect his interpretation to be correct. Miiller's interpretation 
is substantially the same. I have not made sections, but from 
repeated observations of the external appearance of the valve 
I am convinced that their interpretation is not correct. If 
the outer surface of the shell of T. favus is examined under a 
binocular, with a y^th oil-immersion objective, using either oblique 
light or oblique light reflected from the under surface of the 
cover-glass upon the object (the Leitz dark-ground illuminator, 
when decentred, acts admirably for this purpose), a thin plate of 
silex closing the external opening is very distinctly evident, for 
light-reflections and shadows can be very clearly seen upon it, 
and are seen to move over its surface when the mirror is slightly 
moved. The appearance is represented in fig. 15, made from a 
camera-lucida drawing, in which the outline was made by viewing 
it under a monocular, with central light, at a magnification of 
1,500 diameters, and the shading put in to show its appearance 
as seen under a binocular at the same magnification with oblique 
light, the chamber chosen being midway on the slope between the 
apex of the convexity of the outer surface of the valve and the 
margin. This closing membrane I believe to be very thin, and 
probably any section of it that Floegel made would be nearly or 
quite invisible, and therefore easily overlooked. I fail to detect 
any pores in it, although I have examined it by several methods 
of illumination ; but at the same time there is a faint indication 
of some kind of fine-grained surface which may ultimately prove 
to be pore-structure. 

Upon examining the inner surface of the valve at the same 



N. E. BROWN ON THE STRUCTURE OF DIATOMS. 333 

magnification and with oblique illumination, the appearance of 
the closing plate is as shown at fig. 1G, represented for effect as 
at black-dot focus, and drawn and shaded by the same method 
as fig. 15. If, however, it is examined by dark-ground illumi- 
nation, and especially if the illuminator be decentred so as to 
reflect the light from the under surface of the cover-glass upon 
the diatom, the closing plates appear to be much more raised 
than as seen by oblique light and nearly hemispherical ; which, 
however, is the correct appearance I am unable to say. Both 
forms of illumination distinctly demonstrate that the outer and 
inner closing plates have their central part raised above their 
marginal attachment, or, in other words, each closing plate is 
separated from its neighbours by a furrow. Floegel and Miiller, 
however, both represent the inner plate as perfectly flat and 
even, and continuous with that of the adjoining chambers, and in 
their drawings (which I think must be somewhat diagrammatic) 
of considerable relative thickness. Floegel represents the inner 
plate as containing small cavities in its substance, closed on all 
sides. Miiller, in the figure he published in 1898, represents the 
plate as having small perforations through its substance, whilst 
in that published in 1899 he represents the plate as having 
small concave pits extending half-way through its substance on 
the side facing the interior of the diatom. This latter view is, 
I believe, much more correct than the other two interpretations, 
for I find that at a magnification of 3,000 diameters, when the 
light is oblique, or reflected upon it from the inner surface of the 
cover-glass, so that the plate is of a dull greyish-white colour, 
it is clearly seen to have pit-like cavities in it closed by a 
membrane which is probably situated at the other surface of 
the plate. These pits can be clearly demonstrated by gently 
moving the mirror, when the shadow formed by the wall of the 
pit is seen to move round upon the membrane at the bottom of 
the pit. The appearance of the pits as seen with the light 
reflected upon them from the under surface of the cover-glass at 
a magnification of 3,000 diameters, but enlarged to somewhere 
about 10,000 diameters, is as represented at fig. 17. This mem- 
brane under this form of illumination is white, and is probably 
very thin. When viewed with central light and accurately in 
focus, it appears more transparent than the thicker plate- 
substance, and the light shows through it more brightly. But 



334 N. E. BROWN ON THE STRUCTURE OF DIATOMS. 

when examined under dark-ground illumination the reverse 
sterns the case, for then the plate-substance appears to have 
the transparent of a black sky, and the membrane of the pits 
reflects the light so as to appear like minute golden stars. It is 
by some refractive or diffractive property of this membrane that 
the black-dot appearance is produced, for when the membrane 
itself is accurately in focus no black dot is seen ; but if the focal 
plane of the lens is above the focus of the membrane, then the 
black-dot appearance is produced, and appears to me nothing 
more than a deceptive light effect. From the different appear- 
ances of this membrane under different methods of illumination 
and its contrast with that of the plate, I think it must be of a 
somewhat different nature. Although I suspect that it is per- 
forated, I have quite failed to perceive any trace of pores in it ; 
higher magnification than I am able to obtain is probably needed 
for demonstrating anything of that nature. 

In conclusion, from the evidence afforded by Mr. Capell's slide 
and from the observations I have made upon other diatoms not 
hastily formed opinions, but based upon many hours' examination 
under all forms of illumination it seems clear that we can no 
longer regard all the black dots usually seen upon diatoms as 
being pores through the shell, although there may be cases 
where they are so ; for in the cases examined they are certainly 
nothing more than light effects or shadows, either caused by the 
nodes of the grating structure, as in Pleurosigma ; or by the 
membrane closing the meshes of the grating, as in Stauroneis ; 
or by the membrane closing the pits in the cell-wall, as in 
Triceratium. 

What I take to be the true pores must be sought for in the 
thin membrane of silex closing the meshes or pits. If these 
are not pores, then I do not know where we are to seek for them. 
I think it must be perfectly obvious, to all who like myself have 
carefully studied the movements of living diatoms, that there 
must be openings or pores through the shell communicating with 
the interior. This seems also conclusively proved in cases where 
the shell certainly has chambers in its substance, as in Triceratium 
favus, Pleurosigma angulatum and others, for in the ordinary 
process of mounting the medium penetrates easily into the 
interior of the cavities, and they can also be filled by chemical 
deposits, which I do not think would be the case if the membranes 



N. E. BROWN OX THE STRUCTURE OF DIATOMS. 335 

closing these cavities were solid, imperforated films of silex ; no 
osmotic theory will account for it. 

Also it is quite certain that there is some extrusion of motile 
living matter from the interior to the exterior of the diatom, 
which is controlUd by the will of the organism. 

No one has yet been able to detect any protoplasmic filaments 
or pseudopodia (other than the crest of protoplasm along the 
raphe) protruding from the pores of diatoms, and if they are as 
fine as the pores I have seen would seem to indicate, and as trans- 
parent as protoplasm, I doubt if we ever shall see them on the 
living diatom, as the nearness of their own refractive index to 
that of water would not provide sufficient contrast to enable us 
to detect them. Killing and staining do not seem to prove 
successful in demonstrating anything of the nature of pseudopodia, 
only the crest at the raphe and a very thin layer of protoplasm 
sometimes covering the whole shell can be made evident, 
so far as I have been able to demonstrate it, but it ought not to 
be lost sight of that there is a possibility that a diatom may be 
able to speedily retract any protoplasmic matter that it may 
protrude from its shell or from the film of protoplasm that some- 
times covers its shell, so that at the slightest indication of the pre- 
sence of anything injurious, all external protoplasm of the nature 
of pseudopodia may be suddenly withdrawn before the diatom is 
killed. Usually there is no evidence that any living matter is 
protruded to any distinct distance from the shell, except at the 
raphe, as any substances taken hold of by a diatom are generally 
seen in apparent close contact with the shell, although occasionally 
one is seen dragging a niece of dirt along at a short distance 
behind it by an invisible thread. But upon a few rare occasions 
I have witnessed a diatom seize and move pieces of dirt that were 
at an appreciable distance from the shell, and on one occasion 
last autumn I was able to measure the interval between the 
diatom and the dirt. I was observing a large species of Surirella, 
probably S. biseriata, which was moving rather quickly across the 
field, when I saw it seize with invisible hands a large piece of dirt 
at a little distance from it, and pull it along by its side, without 
decreasing the distance between itself and the dirt. I at once put 
on an eye-piece with a micrometer scale on it, and carefully noted 
the distance separating the dirt and diatom upon the scale, and 
then substituted a stage micrometer for the diatom and found that 



336 N. E. BROWN ON THE STRUCTURE OF DIATOMS. 

the distance to which the pseudopodia (if I may term them so) 
extended was between 1/3, 000th and 1/4, 000th of an inch. After 
carrying it along across about one-third of the field of view, 
it released its hold of the dirt, and in doing so I saw it give a 
very slight but distinct jerk, just as if something had snapped 
suddenly, for the mass of dirt was very much larger than itself. 
This observation was made with a fth lens. 

Finally a word as to the pores. It must not be expected that 
they can be rendered visible in as easy a manner as Surirella 
gemma can be resolved into dots, for they cannot ; they are so 
extremely minute that they are by no means easy to detect. 
To make them out at all a Tjyth. or xV^ n oil-immersion of 
1ST. A. 1*3 is necessary, with eye-pieces of sufficient power to bring 
the magnification up to at least 1,000 diameters, and often not 
less than 2,000 diameters is really required to make the structure 
clear, combined with very careful manipulation, a most exact 
arrangement of the light and a fair stock of patience. Some can 
be seen with central light, but for the most parti have found that 
the easiest way to render them visible is by means of a Leitz 
dark-ground illuminator, from which, by decentring it, various 
modifications of oblique light and light reflected from the under 
surface of the cover-glass can be obtained. This method of 
reflecting light upon a diatom from the under surface of the 
cover-glass may not be generally known, but it can be accom- 
plished by decentring the condenser or dark-ground illuminator, 
and then raising or lowering it slightly until the right effect is 
produced. The process is not a difficult operation, but requires a 
little practice, and very often features can be seen much more 
clearly by this method than by any other. It is like viewing an 
object upon which the sun is shining, with the back to the sun. 
When examining a diatom by means of the Leitz illuminator no 
funnel-stop must be used in the lens to cut down its aperture. 
Sometimes a rather dim light is better than a bright one for 
rendering the structure conspicuous. 

The lowest power with which I have been able to see the pores 
in the films of Pleurosigma balticum is Powell & Lealand's 
excellent |-th water-immersion, with which, in combination with 
a X 18 eye-piece, they are just perceptible. A Leitz ygth or 
yg-th oil-immersion will also demonstrate them and those of 
other species, but the lens I have chiefly used has been a Iteichert 



N. E. BROWN ON THE STRUCTURE OF DIATOMS. 337 

y^th oil-immersion of N.A. 1*3, on account of its greater 
magnification, as it is really a xjth, not a true y^th. 

Description of Plate 23. 

Fig. 1. Part of one of the outer films of the outer grating of 
Pleurosigma balticum, x 3,000. The central part from a camera- 
lucida drawing, the remainder added to scale from various parts 
of the films, to show the manner in which the bars project and 
are held in place by the pore-perforated membrane of silex. 
Realgar mount, central light, no stop. 

Fig. 2. Part of a curved bar from a partly dissolved specimen 
of Pleurosigma balticum, which presents both dorsal and edge 
views, drawn as seen, to a scale of about 9,000 diameters. 
Realgar mount, central light, no stop. 

Fig. 3. Part of the grating of Swrirella gemma, x 3,000. 
Realgar mount, central light, no stop. 

Fig. 4. Four meshes of the same enlarged to the scale of 9,000 
diameters. 

Fig. 5. Fragment of the film overlaying the outer grating of 
Pleurosigma angulatum, X 3,000. Realgar mount, Leitz dark- 
ground illuminator, without a funnel-stop at the back of the 
objective. 

Fig. 6. Diagrammatic enlargement of the bars of the film 
over the outer grating of P. angulatum, to show the manner in 
which they appear to overlie one another, drawn to a scale 
of 6,000 diameters. No pores could be seen when this appear- 
ance is visible. 

Fig. 7. Outer and inner grating of P. angulatum under the 
film of diamond-shaped meshes, x 3,000. Realgar mount. 

Fig. 8. Two meshes of the same enlarged to 9,000 diameters. 

Fig. 9. Outer grating of P. angulatum, seen at the focus 
immediately preceding the hexagonal appearance of fig. 7, 
x 3,000. Realgar mount. 

Fig. 10. Fragment of the grating of Xavicula serians, x 3,000. 
Picric-piperine mount ; upper part showing the coarse inner 
grating, as seen with central light and a central stop in the con- 
denser, green screen ; lower part showing the outer grating 
superposed upon the coarser grating, as seen illuminated by a 
Leitz dark-ground illuminator^ 



338 N. E. BROWN ON THE STRUCTURE OF DIATOMS. 

Fig. 1 1 . Fragment of the shell of Xitzschia scalar is, showing 
pores, x 3,000. Styrax mount, central light, green screen. 

Fig. 12. Fragment of the grating of Amphipleura Lindheimeri, 
X 3,000. Styrax mount, central light, green screen. 

Fig. 13. Fragment of the shell of a small species of Pinnularia 
from the Cherryfielcl deposit, x 3,000, showing what are believed 
to be a row of pores down the centre of the outer wall of each 
cavity. Picric-piperine mount, central light and green screen ; 
can also be seen with dark-ground illumination without a funnel- 
stop in the lens and no green screen. 

Fig. 14. Fragment of the grating of Stauroneis ])hoenicenteron, 
x 3,000. Picric-piperine mount, oblique illumination by Leitz 
dark-ground illuminator. 

Fig. 15. View of one of the hexagonal cavities of the valve of 
Triceratiam favus as seen from the outside of the diatom, showing 
the membrane which closes it on the outer side, x 1,500. Styrax 
mount ; outline drawn with a camera-lucida as seen under a 
monocular, shading added as seen under a binocular with oblique 
illumination. 

Fig. 16. View of one of the hexagonal cavities of the valve of 
Triceratium javus as seen from the interior of the diatom, showing 
the raised appearance of the membrane, x 1,500. Styrax mount, 
drawn in the same manner as fig. 15. 

Fig. 17. Fragment of the membrane shown in fig. 16, drawn as 
seen at a magnification of 3,000 diameters, but enlarged to about 
10,000 diameters, to show the pit-like nature of the dots upon 
the membrane. 



Joi'.m. Qucl-ett Microscopical Club. Scr. 2, Vol. XII. No. 74, April 1914. 



Jourx. O.M.C. 

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Structure of Diatoms. 



339 



NOTICES OF BOOKS. 

Handbook of Photomicrography. By H. Lloyd Hind, B.Sc, 
F.I.C., and W. Brough Randies, B.Sc. 8| x 5 j in., xii + 
292 pages, 44 plates and 71 text illustrations. London, 
1913 : G. Rout ledge & Sons, Ltd. Price 7s. 6d. net. 

The student of photomicrography, whether he approach the 
subject from the side of photography or microscopy, can hardly 
complain of the lack of manuals whose aim is to guide him 
in this fascinating subject. The photographer, in reading 
Messrs. Hind and Randies' handbook, may perhaps be surprised 
that so much space is devoted to details concerning the micro- 
scope and its accessories; but he must remember that in order 
to photograph an object under the microscope it is very essential 
he should possess the necessary knowledge of the instrument 
to obtain the best results visually. 

Although the subject is treated by the authors in an ele- 
mentary manner, at the same time, however, the processes are 
discussed in sufficient detail to be of use in research. A special 
feature of the book is the very numerous illustrations, and with 
each photomicrograph reproduced full details are given of the 
process and apparatus used and the method of developing the 
negative. This very useful feature enables any special worker 
to select the best means for his own branch of the subject, 
whether it be the photography of the minute details of diatoms, 
the stained sections for use in the histology of plants and 
animals, or rock sections and crystals under polarised light. 
The subject of colour photomicrography is dealt with in 
Chapter XIII. The utility of the Autochrome and Paget plates 
for registering the appearance of thin rock sections under 
polarised light was excellently demonstrated at a recent meeting 
of The Photomicrographic Society. 

The subject of cinema-micrography is referred to, but this 
could hardly be dealt with fully in an elementary textbook. 
In fact, as a means of research it is in its infancy, but fruitful 
results may be expected in the future in the study of the 
life-history and movements of micro-organisms. 

There are useful formulae and tables at the end of the book 
and an index. Both authors and publishers may be congratu- 
lated on the appearance of the book. 

Journ. Q. M. C, Series II. No. 74. 24 



340 



PROCEEDINGS 

OF THE 

QUEKETT MICROSCOPICAL CLUB. 

At the 492nd ordinary meeting of the Club, held on October 28th, 
1913, the President, Prof. A. Dendy, D.Sc, F.R.S., in the chair, 
the minutes of the meeting held on June 24th, 1913, were read 
and confirmed. 

Mr. S. G. H. Knox was balloted for and duly elected a member 
of the Club. 

The Hon. Secretary said they were favoured with the presence 
of several visitors, to whom he offered a hearty welcome on behalf 
of the Club. 

The President said that members would be sorry to hear that 
since the last ordinary meeting the Club has sustained the loss of 
one of our more well-known members : the Right Hon. Sir Ford 
North, F.R.S., died on October 12th, at the age of eighty-three. 
He was a Fellow of the Royal Society, and a keen entomologist. 
He was elected a member of the Club in 1894, became a member 
of the committee in 1899, and was one of the vice-presidents from 
February 1901. His patience and experience in directing a 
meeting when he occupied the chair made him a most valuable 
member of the Club, and one whose loss will be much regretted. 

Mr. E. J. Spitta said that Sir Ford North hardly ever missed 
attending the meetings of the Club, and he thought that a more 
charming man never existed. Often in committee he would 
remain silent for a long time, and would then rap out a very 
clever opinion on the matter before them. During the four years 
of his (Mr. Spitta's) presidency he had frequent opportunities of 
intercourse with Sir Ford North, and on every occasion had found 
him a courteous friend. 

Mr. Spitta then moved: "That the Committee be empowered 
through the Secretary to convey to the relatives of the late Sir 
Ford North an expression of their regret and sympathy." 

This having been put to the meeting, it was unanimously 
carried by the members present silently rising. 



PROCEEDINGS OF THE QUEKETT MICROSCOPICAL CLUB. 341 

The list of donations to the Club was read, and the thanks of 
the members were voted to the donors. 

Mr. S. C. Akehurst (Hon. librarian) read a note on "A 
Changer for Use with Sub-stage Condensers." The method of 
using the changer was demonstrated to the members. 

Mr. S. C. Akehurst also read a note on " A Trap for Free- 
swimming Organisms." Two forms of the little piece of apparatus 
were exhibited, and details demonstrated by drawings on the 
blackboard. 

The President said he had examined the extremely ingenious 
contrivance for quickly changing the condenser. It was a matter 
which very strongly appealed to him, as he had often much 
trouble in changing condensers. 

Mr. D. J. Scourfield, referring to the trap for free-swimming 
organisms, said this method opened new possibilities w T hen 
dealing with extremely minute organisms. One can get to a 
certain point with the centrifuge ; but it is sometimes desired to 
go a little further in concentrating. He thought it a very 
ingenious piece of apparatus. 

A paper on " The Gastrotricha," communicated by Mr. James 
Murray, F.R.S.E., was introduced by Mr. Scourfield, who said 
that it was just twenty-four years since the subject had pre- 
viously been brought before the notice of the Club. This was 
a paper read by T. Spencer on September 27, 1889, on a new 
species he provisionally named Polyarthra fasiforniis. This is 
now Stylochaeta fusiformis. Mi 1 . Murray said that he had 
been reluctant to attempt an introduction to the study of the 
Gastrotricha, as his knowledge of the group was by no means 
profound, and had been only recently acquired. The main part 
of the paper is an annotated bibliography which it was hoped 
would save students much of the trouble the author had ex- 
perienced. If the bibliography be too condensed, the student is 
always liable to suspect that a work omitted from it has not 
come to the knowledge of the compiler. Here, however, all 
important general, biological and systematic works known to 
the author are included, as well as any really important 
faunistic studies. Every work is given in which new, or sup- 
posed new, species or groups of higher value are described. It 
is unfortunate that the Gastrotricha which include those old 
familiar friends of the students of pond-life, Chaetonotus lanes 



342 PROCEEDINGS OF THE 

and Ichthydium podura have no popular name. Gosse pro- 
posed the name of " hairy-backed animalcules." This is entirely 
unsuitable, since some of the genera are not hairy-backed 
(Ichthydium, Lepidoderma). Mr. Murray was not able to suggest 
an appropriate name. The name suggested by the scientific 
term for the whole group, which embodies almost the only 
character which they all possess, is unsuitable for popular use. 
The Gastrotricha are not animals which can be named offhand. 
The days when we found Chaetonotus lanes and Ichthydium 
podura, occasionally varied by C. maximus, on all our pond-life 
excursions are over. There is a host of species which have 
contributed to the records of C. larus. These species are all 
alike to a casual glance, but are distinguished by minute 
characters the possession of small branches by certain of the 
bristles, the form of the minute scales which bear the bristles, 
etc. Some of these are so delicate that an oil-immersion lens 
would be needed for their certain determination. The author 
expressed his thanks to Messrs. Rousselet, Bryce and Starring 
for assistance given in the preparation of this paper. The paper 
then goes on to describe the form and structure of the Gastro- 
tricha, their haunts and habits, an historical sketch of the 
genera, their classification, a key to the genera and a list of 
the eighty-three species which have been described, notes on the 
identification of species and on some species Mr. Murray had seen, 
and concludes with a bibliography of seventy-two items. Mr. 
Scourfield illustrated his remarks and comments by references to 
a number of sketches he had drawn on the blackboard. 

The President had much appreciated Mr. Scourfield's resume 
of Mr. Murray's paper. He referred to the " fish-hook " spines 
and other extraordinary specific characters, which, he thought, 
could not possibly be explained as due to natural selection. The 
Club was very much to be congratulated on having such an 
important paper contributed to the Journal. 

Mr. llousselet said these organisms could be preserved quite 
well in 5-per-cent. formalin. He remembered Mr. Spencer's 
paper in 1889 quite well, and had differed from him at the 
time, and had said fusiformis was not a rotifer, but could 
not then say what it was. The animal was taken at a Club 
excursion. 

On the motion of the President a cordial vote of thanks was 



QUEKETT MICROSCOPICAL CLUB. 343 

passed to Mr. Murray for his paper and to Mr. Scourfield for 
giving them so good a resume of it. 

Mr. James Grundy described and exhibited "An Improved 
Form of Cheshire's Apertometer." 

Mr. Grundy said that of the value of Mr. Cheshire's form of 
apertometer there can be no doubt. The aim of Mr. Nelson has 
been to enable the N.A. values of an objective to be read on the 
apertometer easily and accurately. Distinctness and clearness of 
reading have been effected by increasing the number of marked 
values of N.A. from 9 to 22 without the confusion that over- 
crowding of the lines would entail. To accomplish this, short 
arcs of circles are used instead of whole circles. A valuable pro- 
perty of these is the clear visibility of the ends or edges of the 
arcs : they are seen more distinctly than complete circles would 
be. The contrast between the white ground and the short black 
lines favours this. The exterior edges of the arcs denote the N.A., 
and thus give most convenient, accurate, and definite positions for 
reading. 

Mr. F. J. Cheshire said it might interest members to know 
that he described his apertometer before the Club some ten years 
ago. When Zeiss first issued Abbe's form, it was marked to read 
only to 005. In a paper defending this marking, read before the 
R.M.S. in 1880, Abbe dealt with the accuracy it was necessary 
to strive for. On the Zeiss apertometer it is possible to read to 
| per cent. ; but blue rays alone will give a difference of 1 per 
cent, over a reading taken with red light, so that the maximum 
accuracy it was advisable to attempt to obtain was 1 per cent. 
Mr. Cheshire thought that one point in Mr. Nelson's diagram 
largely vitiates the advantages given by a greater number of 
fiducial Hues that is, that the fiducial edge in the diagram is 
the outer edge of the line ; and, again, the lines are of varying 
thickness. There are twenty-two edges of lines on the diagram 
with no fiducial value. He himself thought that his original 
form was not capable of further accuracy. Mr. Cheshire then 
described, and subsequently demonstrated, another method of 
measuring N.A., which he considered an improvement on the 
older form. 

A visitor Mr. M. A. Ainslie, K.N. said that experience in 
the use of both the original form of Cheshire's apertometer and 
the modification thereof recently suggested by Mr. Nelson has 



344 PROCEEDINGS OF THE 

revealed one or two difficulties in connection with the reading of 
the instrument that is, if any accuracy in the second decimal 
place is required. The first difficulty is due to the fact that in 
Mr. Cheshire's instrument we have to interpolate or estimate 
between two divisions on a scale, one of which is not visible, being 
outside (apparently) the margin of the back lens of the objective. 
This renders the estimation of the second place of decimals in the 
N.A. uncertain,' and although Mr. Nelson's modification of the 
original instrument is somewhat better in this respect, yet the 
very means adopted to improve the reading namely, the intro- 
duction of a large number of additional circles is likely to con- 
fuse the diagram and bewilder the observer. In either the old 
form or the new of Cheshire's instrument, a count has to be made 
of concentric circles a thing which, simple as it may seem, is 
peculiarly liable to confuse the eye, so that it is only after count- 
ing several times that one feels certain that the number is, say, 
eight, and not seven. 

Mr. Ainslie exhibited and described a new method of reading 
the N.A. of an objective, 

The President said the Club was much indebted to Mr. Ainslie 
for his communication, and also to Mr. Cheshire and Mr. Grundy, 
to whom the thanks of the meeting were unanimously voted. 



At the 493rd ordinary meeting of the Club, held on Novem- 
ber 25th, 1913, the President, Prof. A. Dendy, D.Sc., F.R.S., 
in the chair, the minutes of the meeting held on October 28th, 
1913, were read and confirmed. 

Messrs. W. M. Bale, B. Shepherd, H. Dobell, E. W. Ramsay, 
M. R. Licldon, A. Panichelli, Robert Young, W. G. Tilling, and 
E. J. E. Creese were balloted for and duly elected members of 
the Club. 

The President read a letter from the nephew of the late Sir 
Ford North, which was in reply to the vote of sympathy passed 
at the last meeting. 

Mr. C. E. Heath, F.R.M.S., brought before the notice of the 
meeting a device for preventing damage to objective or slide, 
especially when the higher powers are used, in cases where the 
microscope is liable to unskilful usage, as, e.g., at soirees. A 
small piece of thin metal steel was suggested is taken, having 



QUEKETT MICROSCOPICAL CLUB. 345 

a hole in it of such a size as to permit of the screw-end of an 
objective passing through it up to its flange. In use the plate is 
placed over the end of the nose-piece, and the objective screwed 
home through it. To a projecting portion of the metal plate is 
fitted a short length of brass tube or rod say | in. diameter, 
which has been tapped internally, the direction of the tube being 
parallel to the optic axis, and just clear of the objective. A fine 
screw (25 threads to an inch) is fitted to the tube, and at the 
lower end is provided with a milled head. The microscope is 
focused in the usual way, and the screw then screwed down until 
it is in contact with the stage clear of the cover-glass, and so 
prevents any movement of the body, and possible damage. If 
required, a small amount of slack may be left for possible focusing 
by visitors who can use a microscope. 

The President described " A Red- Water Phenomenon due to 
Euglena." He had noticed a curious appearance in a pond near 
Manchester : the water was of a brilliant red colour. This, on 
examination, proved to be due to Euglena, which formed quite a 
thick scum of the red colour. The colour was confined to the 
surface, and had a dry, powdery appearance that was very notice- 
able. Microscopic examination showed the Euglena to be of a 
large species, and the red coloration to be due to the replace- 
ment of the chlorophyll by haematochrome. The main mass of 
the body was coloured. Those floating on the surface were in a 
resting condition ; but, at the bottom, all were actively swimming 
about. There was apparently no intermediate stage, and at once 
the question arose : How did the organisms get from the bottom 
to the top of the pond % It was found that the Euglenae at the 
bottom of the pond secreted large quantities of mucilage. The 
organism, in the presence of sunlight, gave off bubbles of oxygen, 
which became entangled in the mass of mucilage, and presently 
carried the mass to the surface, trailing Euglenae after it, so that 
they were collected at, and formed a scum on, the surface. The 
colour of the scum changed during the day, from red in the 
morning to green in the afternoon, the actual change from one to 
the other being accomplished in about half an hour. Cunning- 
ham had observed similar changes in Euglena viridis, near 
Calcutta, lie records the scum as bright red in the morning 
dull red at midday, and green in the evening, and by sunset an 
intensely vivid green. The reverse took place just about dawn, 



346 PROCEEDINGS OF THE 

so that at sunrise the pond scum was brilliant red again. The 
President asked if any members had seen a similar appearance. 

Mr. C. F. Rousselet, when in South Africa with the British 
Association in 1905, had noted near the Matoppo hills a similar 
red Euglena, which he had not before seen. 

The Hon. Sec. paid considerable attention to the " Breaking of 
the Meres," but had never seen red Euglena. He had observed 
red scum, due to other causes. The phenomenon noticed by the 
President was, however, not unique in this country. Some years 
ago he had received some " red scum " material from Norfolk, 
which was definitely identified as Euglena. The organisms were 
crowded in their middle region with starch grains, and starch in 
such a form that it was not affected by iodine. 

Mr. A. E. Hilton asked whether the red colour indicated the 
decay of the chlorophyll formed during the previous day. 

The President did not think that the change from green to red 
indicated any process of decay this change of colour was not 
unique in Nature, as the snow plant could be obtained both red 
and green, and apparently the change was due to nitrogen starva- 
tion. He found this to be the probable cause when he had two 
jars side by side, one red and the other green, and a fly had 
fallen into one jar and had decayed ; the slightest trace of nitro- 
genous food was sufficient to cause the change, which he thought 
could not be regarded as a product of decomposition. Dr. 
Cunningham thought that both kinds of pigment were present at 
the same time, but that they were differently placed when the 
change of colour was observed ; but whether this was the sole 
reason for the change in the Euglenae was not certain. 

Mr. James Burton (Hon. Secretary) read a short paper, 
" On the Disc-like Termination of the Flagellum in certain 
Euglenae." 

Mr. James Burton also read a note on " A Method of Marking 
a Given Object on a Mounted Slide." 

Mr. M. Blood said he usually put a spot of ink on the bright 
spot of light formed on the slide by a high-power condenser, and 
when it was dry, scraped the centre away. 

Mr. Spitta, after finding and centring the object in the field, 
replaced the objective with a dummy of similar size, on to the lower 
end of which had been fastened a rubber letter 0, such as is to be 
obtained in small movable-type printing outfits. The letter is. 



QUEKETT MICROSCOPICAL CLUB. 347 

inked, and gently lowered on to the slide. He had found this 
method quite satisfactory. 

Mr. James Grundy read a paper communicated by Mr. E. M. 
Nelson on " The Measurement of the Initial Magnifying Powers 
of Objectives." Mr. Grundy added a few notes in amplification 
and explanation of some points in Mr. Nelson's paper, which he 
illustrated with blackboard diagrams. 

A vote of thanks to Mr. Grundy was carried unanimously. 



At the 494th ordinary meeting of the Club, held on December 
23rd, 1913, Mr. D. J. Scourfield, F.Z.S., F.R.M.S., Vice- 
President, in the chair, the minutes of the meeting held on 
November 25th, 1913, were read and confirmed. 

Messrs. M. A. Ainslie, R. A. Saunders, T. B. Lock, F. S. 
Mumford, A. Green, H. F. W. Sprenger, W. D. Deed and J. H. 
North were balloted for and duly elected members of the Club. 

A letter was read from the Poyal Microscopical Society 
enclosing a copy of a resolution passed by their Council, thanking 
the members of the Q.M.C. who exhibited at their Conversazione 
on November 19th. 

Mr. B. M. Draper read a paper on a new live box for the 
exhibition of flies and other large objects under low powers of the 
microscope the article itself being exhibited in the room under a 
Greenhough binocular. 

Mr. B. M. Draper also read a paper describing a new stop for 
obtaining dark-ground illumination with the Greenhough 
binocular the subject being illustrated by the exhibition of the 
stop and by a diagram upon the blackboard. 

The Chairman thought the live box well adapted for showing 
large objects, and inquired if any means were adopted for con- 
fining the insects or controlling their movements whilst under 
observation. 

Mr. Draper said there was no other means of controlling the 
movement of the objects except by the use of a small cell, but 
the power used being a low one, the whole cell was generally in 
the field at the same time ; and in answer to a question by 
Mr. Rousselet, he said that the cover of the cell was only held 
down by its own weight, but it was prevented from slipping 
sideways by the upright pins mentioned in the paper. 



q 



48 PROCEEDINGS OF THE 



The thanks of the meeting were voted to Mr. Draper for his 
papers. 

Mr. W. R. Traviss exhibited under microscopes two fragments 
of quartz crystals. Referring to one of the mounts, he said it 
showed a series of seven faint lines across the field, parallel, but 
not equally spaced. He suggested that the lines at one time 
were respectively the outer surfaces of the crystal. The plane 
of this particular surface in the mount referred to was at right 
angles to the plane of the microscope stage, so that by focusing 
down one could look along this plane. It was then noted that 
this " old crystal surface " was covered with a number of very 
small crystals, or debris, which had been deposited on this plane. 
Presently the crystal went on growing, and again a period of rest 
and more debris deposited or formed. This was repeated seven 
times, but the exterior face was quite smooth. 

Then as to the occasional presence of contained bubbles of 
liquid in quartz (and other) crystals. It was suggested that it 
was possible that they were formed by a bubble of gas adhering 
to perhaps the under surface of a growing crystal, and material 
being deposited round and over it. 

Some discussion followed on liquid enclosures in crystals and 
the nature and method of identification of the gases contained. 
The chairman drew attention to a paper by Mr. Ashe on the 
effects of temperature on enclosed liquids. (Journ. Q. M. C, Ser. 
2, Vol. VIII., pp. 545-8, pi. 28.) 

Mr. E. M. Nelson sent a note on a peculiar form of diatom. 
During an examination with dark-ground illumination of Mr. 
Siddall's filaments on some Coscinodisci in a diatom gathering, 
mounted and kindly given me by Mr. Chaffey, a small portion 
of sandy grit was found to have similar filaments protruding from 
it. Its colour was a golden yellow, the same as the sandy grit 
usually seen in this kind of slide, which contains diatoms mounted 
in sea-water in their natural state. The dark-ground illumi- 
nator was removed, and when the object was examined by an 
oil-immersion gth with transmitted light from an achromatic 
condenser, the green chlorophyll pustules of a diatom could just 
be made out inside the conglomerated mass of sandy grit. A 
search was then made over the slide, and three or four other 
similar specimens were found. So it appears, then, that there is 
a " caddis-worm " form of a diatom. What species this diatom 



QUEKETT MICROSCOPICAL CLUB. 349 

may be no one can say, for it cannot be seen with sufficient dis- 
tinctness for identification. Probably in its cleaned state it may 
be a very common and well-known form, but had it not been for 
its filaments, its presence in these sandy conglomerations would 
never have been suspected. Other species of diatoms on this slide 
were quite free from sandy grit. 

Mr. Nelson ako sent a note on Amphipleura Lindheimeri. 



At the 495th ordinary meeting of the Club, held on January 
27th, the President, Prof. A. Dendy, D.Sc, F.R.S., in the 
chair, the minutes of the meeting held on December 23rd, 1913, 
were read and confirmed. 

Messrs. H. A. Gee, G. H. Shelley, A. Walker, the Rev. G. H. 
Nail, Lieut.-Col. J. Clibborn and L. E. Harris were balloted for 
and duly elected members of the Club. 

The list of nominations by the Committee of officers for the 
ensuing year was then made there being no change from that 
elected last year. 

The President having mentioned that four members of the 
Committee Messrs. Wilson, Heron- Allen, Bryce and Caffyn 
would retire by rotation, but were eligible for re-election, except 
Mr. Caffyn, who did not wish to serve again, asked for nomina- 
tions of members to fill the vacancies created. 

The following gentlemen were thereupon nominated : Messrs. 
Heron -Allen, Wilson, Bryce, Gabb, A. Morley Jones and Todd, 
whose names would appear on the voting paper at the next 
ordinary meeting. 

Mr. A. E. Hilton was then elected as Auditor on behalf of the 
members. 

Mr. S. C. Akehurst (Hon. Librarian) read " Some Remarks on 
Sub-stage Illumination " ; the subject was illustrated by a number 
of photographs projected upon the screen. 

Mr. T. A. O'Donohoe read a paper, entitled "An Attempt to 
resolve Pinnularia nobilis" This was illustrated by photographs 
projected upon the screen. 

Mr. M. A. Ainslie said that the whole question of diffraction 
spectra was of course of vital importance in the resolution of any 
fine structure, and in many cases it could not be done with a dry 
lens. By means of diagrams drawn on the blackboard as he pro- 



350 PROCEEDINGS OF THE 

ceeded, the speaker showed the effects of diffraction spectra under 
varied conditions. In using annular illumination they were 
using a number of central cones of illumination overlapping to 
form the annular. He also pointed out the danger of using 
annular illumination unless great care was exercised as to the 
tube length. 

Mr. Blood said it was extremely easy to resolve diatoms with a 
central stop in which case they were merely seeing the image of 
the stop. In many objectives the central portion and the 
extreme edge were over corrected, but the intermediate zone was 
quite right. 

Mr. Brown said he had been examining Pinnularia nobilis for 
the last forty years, and thought he had obtained a resolution of 
it, but not the same as that described by Mr. O'Donohoe. For a 
long time he was unable to get any resolution, but he believed he 
had now done so, and hoped shortly to read a paper on the subject. 

Mr. Akehurst explained that the photographs shown in illus- 
tration of his paper were taken to show the contrast between the 
ordinary and the new method of illumination with central stop 
below the condenser, but without cutting down the N.A. of the 
objective. 

Votes of thanks were cordially passed to Mr. Akehurst and 
Mr. O'Donohoe for their papers. 

In place of the usual monthly conversational meeting, a Conver- 
sazione was held on February 10th, in the Great Hall, King's 
College, by kind permission of the Principal. Nearly five hundred 
members and visitors were present, and about 170 microscopes, 
besides other apparatus, were on exhibition. It is not possible to 
give a complete list of the objects shown ; but among others may 
be mentioned a number of coloured drawings of water-mites, 
including a series of fifteen figures illustrating the life-history of 
Hydrachna ylobosa (de Geer), by C. D. Soar ; foraminifera under 
microscopes, and material from the sea-bottom in various stages 
of preparation, by Messrs. Heron-Allen and Earland ; living- 
rotifers by Messrs. Bryce, Dunstall, Rousselet, Scourfield and 
others ; stereophoto-micrographs by Messrs. A, E. Smith and 
Taverner ; photomicrographic apparatus and some sixty natural- 
colour lantern-slides by E. Cuzner ; some fine photomicrographs 
in colour of polarised rock sections by Messrs. Cafiyn and Ogilvy. 



QUEKETT MICROSCOPICAL CLUB. 351 

Mr. H. F. Angus (H. F. Angus & Co.) showed the Reichert 
demonstration and comparison eye-piece for comparing the fields 
from two microscopes in one eye-piece, in which the field is divided 
laterally, Akehurst's phototropic pond-life trap, Draper's all-glass 
live box, the Finlayson revolving disc for the exhibition of a 
series of opaque objects, Heath's objective-guard, etc. 

Mr. Lees dirties (C. Baker) had on view several Greenhough 
binocular microscopes, multicolour illumination of crystals, and 
three forms of the Cheshire apertometer. 

Mr. C. Beck (R. & J. Beck) exhibited the new model high- 
power binocular, employing a -jVth oil-immersion objective, with 
a very simple and efficient adjustment for inter-pupillary 
distance. 

Mr. J. W. Ogilvy (E. Leitz) showed several new short-tube 
high-power binoculars employing a T Vth oil-immersion objective ; 
a comparison eye-piece for comparing simultaneously complete 
fields of two microscopes; and several examples of the Green- 
hough binocular one especially adapted for metallurgical work. 

Mr. F. W. W. Baker (W. Watson & Sons) exhibited a new 
model Yan Heurck, with 2| in. movement to the stage, and 
complete rotation, also a new workshop metallurgical microscope 
and some twenty microscopes with various objects, including a 
series of seven illustrating the development of the chick from 
twenty-four hours to four clays. 

During the evening a lantern lecture was given in the large 
theatre by Mr. F. W. Watson Baker (Watson & Sons) on " Some 
Microscopical Hows," and subsequently Mr. C. Lees dirties 
(C. Baker) gave a lantern demonstration, in the same place, of 
natural-colour photographs and photomicrographs of miscellaneous 
and microscopic objects prepared by the Paget process. Both 
lectures were well attended and much appreciated. 

Of late years the club has not held conversaziones, and during 
the evening the wish was several times expressed that such 
gatherings should be more frequent, and certainly that no long 
interval should elapse between this and the next. (The last 
conversazione was held nearly seventeen years ago on May 4th, 
1897 in the smaller Queen's Hall.) 



352 



PROCEEDINGS OF THE 



At the 496th ordinary meeting of the Club held on February 
24th, which was also the forty-eighth annual general meeting, 
the President, Prof. A. Dendy, D.Sc, F.R.S., in the chair the 
minutes of the meeting held on January 27th were read and 
confirmed. 

Messrs. A. 0. Gooding and Raymond Finlayson were balloted 
for and duly elected members of the Club. 

The list of donations to the Club were read, and the thanks of 
the members voted to the donors. 

Mr. N. E. Brown and Mr. F. W. Watson Baker having been 
appointed scrutineers, the ballot for the election of officers and 
Council for the ensuing year was proceeded with ; it being sub- 
sequently announced that the following gentlemen had been 
elected as 



President 







Four 
Vice-Presidents 

Treasurer 
Secretary 

Assistant Secretary 
Foreign Secretary . 
Reporter .... 
Librarian . . . 
Curator .... 
Editor .... 

Four Members of 
Committee. 



Prof. Arthur Dendy, D.Sc, F.R.S. 

C. F. Rousselet, F.R.M.S. 

E. J. Spitta, L.R.C.P., M.R.C.S., F.R.A.S 

D. J. Scourfield, F.Z.S., F.R.M.S. 
IProf. E. A. Minchin, M.A., Ph.D., F.R.S. 

Frederick J. Perks. 
James Burton. 
J. H. Pledge, F.R.M.S. 
C. F. Rousselet, F.R.M.S. 
R. T. Lewis, F.R.M.S. 
S. C. Akehurst, F.R.M.S. 

C. J. Sidwell, F.R.M.S. 

A. W. Sheppard, F.Z.S., F.R.M.S. 
(A. Morley Jones. 

E. Heron-Allen, F.L.S., F.Z.S., F.R.M.S. 
J. Wilson, F.R.M.S. 

D. Bryce. 



The Hon. Secretary read the Committee's forty-eighth annual 
report. Fifty-five new members were elected during the past 
year, and the total number is now 441. 

The Hon. Curator reported that 2,000 slides had been borrowed 
by members, and that 192 preparations had been added to the 
collection during the past twelve months. 

The Hon, Treasurer presented the Annual Statement of 



QUEKETT MICROSCOPICAL CLUB. 353 

Accounts and the Balance Sheet for 1913, which had been duly 
audited and found correct. 

The adoption of the Committee's report and the Balance Sheet 
was moved by Mr. A. M or ley Jones and seconded by Mr. 
Morland and carried unanimously. 

Mr. D. J. Scourfield, F.Z.S., F.R.M.S., Vice-President, having 
taken the chair, the annual address was delivered by the President, 
who took as his subject " Organisms and Origins." 

The usual votes of thanks to the President for his address, and 
to the officers of the Club for their services during the past year, 
were carried by the meeting. A special vote of thanks was 
passed to the Hon. Secretary and to Mr. J. Grundy for their 
services in so successfully organising the recent conversazione. 



354 



FORTY-EIGHTH ANNUAL REPORT. 

Your Committee are glad to be able to assure the Club of its 
continued prosperity. During the year ending December 31st, 
1913, fifty-five new members were elected ; this number has been 
equalled only once, and exceeded only once when there were 
fifty-seven elected during the recent years of which any record 
has been found. Eleven have resigned, and four were lost by 
death, leaving the present number 441. Among those lost by 
death should be mentioned the Eight Hon. Sir Ford North, for 
some years a Vice-President and a valued member of the Club. 
An obituary notice appeared in the November number of the 
Journal. 

Both the Ordinary and Gossip Meetings have been well attended, 
in fact on several occasions the number present was somewhat 
more than the capacity of the room would accommodate with 
a due regard to comfort. 

The papers and notes read and exhibits contributed during the 
year were as follows : 

Jan. W. M. Bale, F.B.M.S., of Victoria, Australia. Notes 

on some of the Discoid Diatoms. Communicated by 
the President. 
H. Whitehead, B.Sc. British Freshwater Bhabdo- 

coelida (Planarians). Communicated by J. Wilson. 
C. F. Bousselet, F.B.M.S. The Botifera of Devil's 

Lake : Description of a New Brachionus. 
E. M. Nelson, F.B.M.S. Note on Pleurosigma angu- 
latum ; Note on a Coloured Coma observed in 
examining A. Ralfsii. 
Feb. Prof. A. Dendy, D.Sc, F.B.S. By-products of Organic 

Evolution. Presidential Address. 
March. E. Heron-Allen, F.Z.S., F.L.S., and A. Earland, 
F.B.M.S. On some Foraminifera from the Southern 
Area of the North Sea, dredged by the Fisheries 
cruiser Huxley. 
n D. Bryce. Five New Species of Bdelloid Botifers. 



j? 



>> 



55 



FORTY-EIGHTH ANNUAL RETORT. 355 

April 0. D. Soar, F.L.S., F.R.M.S. Two New Species of 
Water-mites. 
,, G. T. Harris. The Collection and Preservation of the 

Hydroida. 
May. T. A. O'Donohoe The Minute Structure of Coscino- 
discics asteromphalus and of two Species of Pleuro- 
sigraa. 
June. H. Sidebottoin. The Lagenae of the South-West 
Pacific. 
E. M. Nelson, F.R.M.S. On a New Method of Mea- 
suring the Magnifying Power of an Objective. 
Oct. James Murray, F.R.S.E. The Gastrotricha. 

,, E. M. Nelson, F.R.M.S. Note on an Improved Form of 

Apertometer. 
Nov. James Burton. On the Disc- like Termination of the 
Flagellum in some Euglenae. 
James Burton. On a Method of Marking a Given 

Object on a Mounted Slide for Future Reference. 
E. M. Nelson, F.R.MS, On the Measurement of the 
Initial Magnification of Objectives. 
Dec. B. M. Draper. On Dark-ground Illumination with the 

Greenhousdi Binocular. 



>) 



n 



D 



At the Ordinary Meetings the following slides and apparatus 
were exhibited : 

Jan. W. Watson Baker. New Model Microscope, having a 
Side screw Fine Adjustment, and New Objective 
Changer, etc. 
A. A. C. Eliot Merlin, F.R.M.S. Photomicrographs of 

Coscinodiscus heliozoides, showing Pseudopodia. 

March. A. A. C. Eliot Merlin, F.R.M.S. Five Photomicro- 
graphs taken at x 320 of various Diatoms. 

April. Presented by G. T. Harris. Mounted Hydrozoa, ex- 
hibited under Microscopes by Messrs. H. F. Angus 
&Co. 

May. J. Watson, a visitor. A Slide showing Multiple Images 
formed by the Cornea of the Eye of a Bee. 
E. Pitt. Various Microtomes exhibited and explained, 



3> 



with Demonstration of Ribbon Section-cutting 







Journ. Q. M. C, Series II. No. 74. 25 



) 



" 



o56 FORTY-EIGHTH ANNUAL REPORT. 

June. A. A. 0. Eliot Merlin, F.R.M.S. Photomicrograph of 
Foot of Ceylon Spider. 
E. M. Nelson, F.R.M.S. A Slide of Green Trap show- 
ing Structure resembling Vegetable Tissue. 
,, W. Traviss. Apparatus for Use in Pond Hunting, 

enabling a Sample of Water to be obtained at any 
desired Depth. 
,, James Grundy. Apparatus for use in connection with 

E. M. Nelson's paper " On a Method of Measuring 
the Magnifying Power of an Objective." 
Oct. S. C. Akehurst. A Changer for Sub-stage Condensers. 

S. C. Akehurst. Trap for Minute Free-swimming 

Organisms. 
Messrs. Grundy, Cheshire and Ainslie. Various Aper- 
tometers. 
Nov. C. E. Heath, F.R.M.S. Objective Guard for Preventing 

Damage to High-power Objectives. 
Dec. B. M. Draper. A New Form of Transparent " Live 
Box " for the Exhibition of Living Organisms, chiefly 
Insects. Also a Special Form of Stop for Dark- 
grouncl Illumination with a Greenhough Binocular. 
W. Traviss. Specimens of Quartz showing under the 

Microscope a Laminated Structure. 

Your Committee feel that the Club is greatly to be congratu- 
lated on the inclusion in its Journal of such valuable papers. 
Not only is their publication in our Proceedings an honour to the 
Club, but the actual value of the communications as a contribu- 
tion to science, and especially to that always difficult and often 
little-appreciated subject, classification, makes the Journal a 
standard work of reference. The Club has also been the means 
of making known and recording a number of new species among 
the Rotifera, the Entomostraca, and Water-mites, by members 
who are authorities in these several classes. While thanking 
those members who have contributed to the success of the Club, 
the Committee would take this opportunity of urging upon 
others the great advantage of bringing before the Club subjects of 
interest in the form of short papers or notes, and the profit they 
would themselves obtain by putting their knowledge into the 
concrete and definite shape required for this purpose. The 



FORTY-EIGHTH ANNUAL REPORT. 357 

Committee at the same time wish it to be remembered that one 
of the foremost aims of the Club is to assist the amateur and the 
beginner, both by providing papers of a somewhat elementary 
character, and by assuring them that, particular]}' at the Gossip 
Meetings, they will find friends willing and anxious to assist them 
in their efforts in gaining experience in the best methods of using 
their instruments, and in the task of identifying specimens. 

The Librarian reports that there has been a fair demand for 
books during the year, but somewhat less than that for 1912. 
The card index and the numbering and rearrangement of the 
books are nearly completed, and the path cleared for commencing 
the final details of the new edition of the Catalogue. The 
thanks of the Club are due to Messrs. Caffyn, Todd and L. C. 
Bennett for the great amount of assistance they have given the 
Librarian in these matters. 

During the year under review the following volumes have 
been added : 

LIST OF BOOKS PURCHASED SINCE JANUARY 1913. 

British Parasitic Copepoda. T. & A. Scott. Vols I. and II. 
Ray Society. 

Bibliography of the Tunicata, 1469 1910. J. Hopkinson. 
Ray Society. 

Schmidt's Atlas der Diatomaceen-kunde. 4 Vols. 

Light. (For Students ) Edwin Edser. 

British Rust Fungi. N. B. Grove. 

LIST OF BOOKS PRESENTED SINCE JANUARY 1913. 

Presented by the Author, Dr. Eugene Penard : 

Nouvelles recherches sur les Amebes du Groupe 
Terricola. 

Presented by the Publisher, John Murray : 
Problems of Life and Reproduction . . Marcus Hartog. 

Presented by J. Burton : 
Das Phytoplankton pes Susswassers. 



358 FORTY-EIGHTH ANNUAL REPORT. 

Presented by the Author, Henry Whitehead. 
British Freshwater Leeches. 

Presented by Prof. Arthur Dendy : 
Classification and Phylogeny of the Calcareous 

Sponges . . . Arthur Dendy, D.Sc., F.R.S., and 

R. W. Harold Row, B.Sc. 

With a reference list of all the described species systematically 
arranged. 

Presented by the Author, Charles Janet, Limoges : 
Le Volyox and Other Papers. 

Presented by the Authors, E. Heron-Allen and A. Earland. 
Clare Island Survey : Royal Irish Academy. 
Part 64, Foraminifera. 

Presented by the Author, J. W. Gordon : 
Diffraction Images. 

Daring the year ending December 1913 the Library has 
received the following publications : 

Quarterly Journal of Microscojncal Science. 

Victorian Naturalist. 

Mikrokosmos. 

Royal Microscopical Society. 

British Association. 

Royal Institution. 

Geologists' Association. 

Manchester Literary and Philosophical Society. 

Hertfordshire Natural History Society. 

Birmingham Natural History and Philosophical Society. 

Botanical Society of Edinburgh. 

Glasgow Naturalists' Society. 

Croydon Natural History Society. 

Indian Museum (Calcutta). 

Royal Society of New South Wales. 

American Microscopical Society. 

Smithsonian Institution. 

Academy of Natural Science, Philadelphia, 



FORTY-EIGHTH ANNUAL REPORT. 359 

Missouri Botanic Garden. 
Philippine Journal of Science. 
Bergen Museum. 
Lloyd Library, Cincinnati. 
United States National Herbarium. 
Royal Society. Series B. 
Natural History Society of Glasgow. 
Zoologisch-botanischen Gesellschaft, Wien. 
Redia. 

United States National Museum. 
Nuova Notarisia. 
Nyt Magazine. 

Liverpool Microscopical Society. 
Nova Scotian Institute of Sciences. 
Royal Dublin Society. 
University of California. 

Illinois State Laboratory of Natural History. 
Societe Royale de Botanique de Belgique. 
Brighton and Hove Natural History and Philosophical 

Society. 
Essex Naturalist. 
Edinburgh Royal Botanic Garden. 

Northumberland and Durham Natural History Society. 
Torquay Natural History Society. 

There were twelve Excursions during the year, which were well 
attended, the average number present being 20'8. That to the 
Botanic Gardens had the most numerous visitors, namely 35, 
and second to that the grounds of Syon House, Isle worth, with 
33. Though no new species appear to have been recorded at the 
outings, abundant and interesting material was acquired, and as 
always the Excursions were marked by a spirit of comradeship 
and social friendliness, as well as being an opportunity for 
scientific acquisition. It may perhaps be pointed out that scarcely 
as much use is made of the results of the excursions on the 
subsequent Gossip Meetings as is desirable. Our thanks are due 
to the officers of the Botanic Gardens, the East London Water 
Works, and the Surrey Commercial Docks, for their kindness in 
allowing the Club to visit their enclosures for collecting, and 
to the Duke of Northumberland for permitting, through the 



360 FORTY-EIGHTH ANNUAL REPORT. 

kind intervention of his agent, the successful visit to the grounds 
of Syon House. The objects exhibited at the Gossip Meetings 
have been interesting and sometimes noteworthy, but it may be 
well to impress upon new members, and beginners especially, that 
all should make an effort to bring a microscope and some object 
for display on these occasions. Not only is this a duty owed 
to their fellows, but a distinct advantage to themselves; they 
thus become expert in the use of their instruments and in the 
arrangement of their specimens. 

The work of the Curator, carried on for so many years, recently 
under great difficulty owing to ill health, and to the insufficient 
space at his command, is beyond all praise, and the best thanks of 
the Club are hereby tendered to him for his self-denying labours. 
The Curator reports that all slides and apparatus in his charge 
are in good condition, and during the past year a great deal of 
time has been spent in revision and amalgamation of the collec- 
tions. There has been a considerable increase in the number 
of preparations borrowed, upwards of 2,000 having gone out, and 
even then the number has been unavoidably restricted owing 
to cramped storage accommodation. 192 slides have been added, 
72 of them by purchase. The beautiful physiological prepara- 
tions, accompanied by descriptive letterpress and illustrations, 
issued by Dr. Sigmund, of w T hich six series have been added, 
have been in great request. A gap has been filled by the 
presentation of a series of slides, with illustrated description, by 
Mr. Whitehead, of Turbellarian Worms, a group previously un- 
represented in the cabinets. A type collection of Hydrozoa, 
presented by Mr. Harris, has been put to practical use, and, now 
that his accompanying paper has been printed in the Journal, is 
likely to be still further in demand. It is hoped by the issue of 
additional descriptive sets to still further increase the usefulness of 
the cabinets from an educational point of view. With the kind 
co-operation of Mr. Vogeler the Curator has been able to issue a 
supplementary list of part of the botanical preparations added 
since the general catalogue was printed. The hearty thanks of 
the Club are due to Mr. Vogeler for his kind services in printing, 
also to Mr. Bestow for general assistance rendered the Curator, 
and to the various donors of slides. The Committee desires to 
thank the officers generally for the interest they have evinced, 
and the often hard work they have undertaken in carrying on the 



FORTY-EIGHTH ANNUAL fcEPOfct. 361 

business of the Club so successfully. The thanks of the Club are 
due to the editors of The English Mechanic and of Knowledge 
for the reports of the proceedings published in their papers. 

Finally the Committee feel that the Club may look forward 
with all confidence to the future. Enthusiasm and work are 
the means for continuing and increasing the success that has 
attended it from its commencement, and also the means of 
enabling us next year to celebrate the Jubilee of its foundation 
in 1865, by men some of whom happily are still with us to 
note with pride the growth and vitality shown by the Club 
they inaugurated almost half a century ago. 



362 



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A NEW OBJECT GLASS BY ZEISS, AND A NEW 
METHOD OF ILLUMINATION. 

By Edward M. Nelson, F.R.M.S. 
{Read March 24///, 1914.) 

Figs. 1-3. 

As Object Glass upon an entirely new plan has been brought 
out by the firm of Carl Zeiss. This lens has not yet been 
catalogued, but as it will undoubtedly effect a considerable 
change in the construction and use of microscope objectives a 
short account of it may prove of interest to the Club. 

The object glass is a short tube oil- immersion 1 of "9 1ST. A. 
Upon taking it out of its black box the first thing that will be 
noticed is that it is nickeled all over, and the next is that the 
front lens is set in a push tube, and not screwed up as usual ; 
these two new departures from the usual type are also found in 
the oil-immersion T Vth recently issued by this firm. 

In very early times objectives were made on this plan. Both 
Ross and Smith, before 1840, used to screw the front lens to a 
tube, which was pushed on to another holding the back lenses ; 
this tube was then rotated until the best point was found, when 
a small screw was put in at the side to keep the tube in that 
position. 

This form of construction has gone on continuously to the 
present day, especially in the cheaper series of objectives, while 
the more expensive ones, including oil-immersions, have had the 
cells holding the lenses screwed into their proper positions. But 
this type of objective, so far as I am aware, for an oil-immersion 
is quite new, as also is an oil-immersion with a N.A. of less than 
1'0. Now with regard to the performance of this lens, the 
corrections are very perfect ; although no fluorite is used in its 
construction it is very nearly apochromatic, and shows a consider- 
able advance over semi-apochromatism, for only a slight trace of 
outstanding blue can be seen. 

The defining power of this objective is quite remarkable, for it 
surpasses all object glasses of similar aperture I have seen. 

On a M oiler's Probe-platte of 60 diatoms all are resolved except 

Journ. Q. M. C, Series II. No. 75. 26 



364 E. M. NELSON ON A NEW OBJECT GLASS BY ZEISS, 

the two specimens of Amphipleura pellacida. The next most 
difficult diatom to the Amphipleura is the Nitzschia curvula, and 
as this diatom counts 89 thousand per inch it shows what this new 
lens can do with oblique light and a stop, the illuminant being 
an ordinary microscope paraffin lamp with a \ in. wick. With 
axial light, without any stop, the Brazilian Lindheimeri is dotted. 
On M oiler's Typen-platte, with 400 forms, the Nitzschia curvula 
(there called the JV. sigmatella) is very thin and difficult, and the 
lens fails to resolve it, but it easily resolves all the others on that 
line except the Homoeocladia Martiniana, which is more difficult 
than A. pellucida. It resolves the N. crassinervis on that plate 
quite easily, and it will just show the striae on the Grammatophora 
oceanica, which counts 88 thousand to the inch. This diatom is 
probably the G. subtilissima ; anyhow, it is very much finer than 
the diatom of the same name on the Probe-platte. 

The image given by this new lens of the Poclura scale is very 
fine indeed. Undoubtedly in this new objective we have a lens 
of great beauty and power. An important question arises as to 
the influence this lens will have upon our battery of objectives. 

In former times a 2 in., 1 in., a | in., a | in. and ^ in. or 
yg- in. represented a full battery, but now we may have a 
battery consisting of only a | in. and an oil-immersion T V in. 
Here the gap is very wide, and the new lens will fill it very 
satisfactorily. 

This lens will, to a certain extent, supersede the oil-immersion 
T V in. in medical schools and colleges. It is sufficiently powerful 
to do all that is wanted in practical study, but necessarily in 
research work a T V in. of wider aperture is required. For a 
student it will be especially valuable, for it has of course more 
working distance and a larger field than a T V in. 

Another very important point is that, because of its great 
working distance, it does not pick up by capillary attraction an 
unfixed cover-glass. This is a source of great trouble when 
working with a - in. 

Zeiss supply a funnel for reducing the aperture of this objec- 
tive, so that a dark ground may be obtained with an ordinary 
dry condenser and a stop. Of course with an oil-immersion 
condenser no funnel is required. 

Henceforth, for research work, a perfect battery will consist of 
a 2 in., 1 in., | in., ^ in., this iin., and a T V in. oil-immersion. 



AND A NEW METHOD OF ILLUMINATION. 365 

In the Navy, when Dreadnoughts were introduced, old-fashioned 
battleships were scrapped ; so also in microscopical affairs those 
who are wise will scrap all their dry lenses of powers higher than 
3 in. or ^ in. 

One can foresee that the advent of this new lens means much, 
for just as oil-immersions have eclipsed water-immersions, so will 
this new lens supersede the wide-angled dry lens, which cannot 
compete with it in working distance, quality, field, or price. 

It is to be hoped that Zeiss will issue an objective of this class 
for the long as well as for the short tube. The most notable 
feature in this new object glass is the near approach that has 
been made towards apochromatism without the use of fluorspar. 

There is, however, another matter for your notice viz. an 
entirely new way of using an object glass for diatom or other 



a 



Fig. 1. 

resolutions, a method, moreover, for which this new object glass 
is peculiarly suited. The method is so simple that it can be 
explained in a few words : (1) Place the diatom so that the striae 
to be resolved are vertical in the field. (2) Set up a critical 
imawe with the edge of the flame in focus and central to the 
field, and open the diaphragm to its full extent. (3) By means 
of the substage centring screws move the condenser so that the 
image of the flame lies just outside the field of a high-power 
eye- piece (fig. 1). If the striae are within the grip of the object 
glass they will be resolved. 

It just amounts to this, that if one is working at diatoms 
with critical illumination and has need to resolve one, all that is 
necessary is to move the side way adjusting screw of the substage 
and place the flame image just outside the field, and the thing is 
done in an instant, without any trouble with stops, slots, or 
other apparatus. 

You will notice that the amount of the displacement of the 
condenser is very small (say twice the length of a Kavicida rhom- 



366 E. M. NELSON ON A NEW OBJECT GLASS BY ZEISS. 

boides), so that this new kind of illumination must not be 
confused with that from a condenser considerably decentred, 
with the illuminant so placed that the light passes through the 
condenser obliquely, a form of illumination old and well known, 
or rather which used to be well known. 

Although there is no difficulty in executing the necessary 
manipulation, the explanation of how the result is obtained is not 
so easy. First, no direct light from the flame enters the field, but 
it must be remembered that it is not a dark-ground image we are 
dealing with ; for if it were high resolution would fail, as Mr. 
W. B. Stokes has pointed out. The field is not dark, neither is it 
light, but it is a sort of glow ; from whence does this glow come ? 
At first it was thought that it must arise from internal reflections 
in the front lens of the object glass, and that the lens was acting 





Fig. 2. Fig. 



3. 



as its own lieberkiihn, as in fig. 2. But further experiments have 
proved that this is not the case ; no doubt some light may travel 
in that manner, but the amount that does so is quite small, and 
wholly insufficient for the purpose. The main body of this light 
is present owing to spherical aberration in the condenser, which 
gives rise to a very oblique beam, as in fig. 3. For this kind of 
illumination therefore a condenser with spherical aberration is to 
be preferred to one more aplanatic. 

There can be no question about extraneous light from the 
illuminant having anything to do with it, for when a metal 
screen, with a slit the size of the edge of the flame, was placed 
close to the chimney, no difference in the effect was observed. 

This kind of illumination will be of service, for it will enable an 
observer to obtain high resolution with a dry condenser, in an 
instant, without the troublesome manipulations usually necessary. 

Journ. Quekett Microscopical Club, 8a: 2, Vol. XII., No. 7", November 1914. 



307 



A NEW LOW-POWER CONDENSER. 

By Edward M. Nelson, FJR.M.S. 
{Read April 28a, 1914). 

Fig. 4. 

Some time ago 1 pointed out to the Club that microscopists were 
badly off for a low-power condenser, for, so far as I know, there 
is no such appliance to be had. Mr. Curties kindly exhibits- 
to-night one he has made from my formula. This condenser is 
designed as a low-power illuminator, and not at all for the 
purpose of resolving fine diatom striae. With the top on, its 
focus is 1 inch, and with the top off 2 inches.* Both the lenses 
are achromatised, and it will be seen that it is particularly 
achromatic, as well as aplanatic ; it will work from the lowest 
powers up to a | inch. 

The first object I examined with it was a Navicula lyra, with 
a Zeiss 12 mm. apochromat. I have been working with the 
microscope now upwards of forty years, and never before have I 
seen such a perfect image of this diatom. In general work, 
with the lower powers, the flat of the flame of a reading 
lamp is focused upon the object ; this with the 2 inch condenser 
covers a large portion of the field, even of the lowest powers. It 
will give an excellent dark-ground for pond life, etc., up to say a 
| inch objective. This condenser is to be named " Quekett," 
after that illustrious microscopist. 

Speaking of dark backgrounds, there is a great defect in many 
condensers, viz. that the spot is not centred to the optic axis of 
the condenser, because the cell holding the stops is not placed 
accurately on the mount. This is a serious defect, because if the 
stop is not centred, the microscopist is forced to use a much larger 

* This back lens of 2-inch focus when used by itself in a holder forms 
the best "verant" I have seen. It is very useful for the examination 
of large microscopical objects, as well as of flowers, engravings, coin-, 
postage stamps, seals, etc. 



368 



E. M. NELSON ON A NEW LOW-POWER CONDENSER. 



stop than is necessary.* How often one sees a dimly lighted 
object, with a halo of bright fog, on one side of the field, owing 
to the use of an excentric stop larger than is necessary. 

To remedy this defect, Mr. Curties shows a simple centring 
stop-holder made from my design. The stop consists of a disc 
with a hole in it which fits on a pin B ; this I designed for my 
Jubilee microscope, which was made by Powell and exhibited at 
the Club in 1887. 

Why microscopists will have their stops cut out of the sheet, a 
much more expensive plan than a disc fitting on a pin on a spider, 





ZI 




v 



Fig. 4. 

A, lever ; B. flat tube with the stop on pin ; C shows the flat tube placed 
on the lever, with screw for fixing the appliance beneath the iris-box. 

I am unable to tell you. But to return, this pin is fixed to the 
end of a flat tube B, which slides on a flat bar A ; this forms the 
centring adjustment right and left. The centring adjustment 
rectangular to this is in arc, by moving the arm C, which is 
pivoted below the iris box. 

* If, for example, a centred stop of -4-inch diameter is requisite, and 
supposing that the stop carrier is 1 inch out of centre, then a stop of 
6 inch will be required to do the same work as the stop of *4 inch. Now 
the area of a circle of "6 inch diameter is more than double that of a circle 
4 inch diameter ; this shows the great loss of light an excentric stop-holder 
causes. 



Journ. Quek-ett Microscopical Club, Scr. 2, Vol. XII. , No. 75, November 1914. 



369 



BINOCULAR MICROSCOPES. 

By Edward M. Nelson, F.R.M.S. 
(Bead. May 2tth, 1914.) 

Fig. 5. 

In recent years several binoculars have been introduced ; none 
of them, however, can be called new. The first, the Greenough, 
by Zeiss * in 1897 was a twin microscope, a form of binocular 
invented by Pere Cherubin d'Orleans nearly three hundred years 
ago. The second, by F. E. Ives in 1902,f is very similar to one 
designed by Wenham in 1866 as a counterblast to Powell's 
high -power binocular in which the whole beam is sent into 
each eye. % The third is a modification of the second by Messrs. 
Leitz, and the fourth, by Messrs. Beck, is very similar to that 
of Ives. 

Before proceeding, let us enumerate the points gained by 
binocular vision. They are four in number and were stated 
by me in the English Mechanic || as follows : 

1. Stereoscopism, or the power of appreciating solidity. 

2. Increase of apparent magnifying power. 

3. Increase of illumination. 

4. Increase of colour perception. 

The first binocular we have to deal with, viz. the Greenough 
twin microscope, became a practical form owing to the re- 
introduction of the Porro prism by C. D. Ahrens in 1888. 
Obviously, it can only be used with very low powers, but never- 
theless I have had no reason to alter the favourable opinion 
I expressed for this form of binocular when it was first ex- 
hibited by Messrs. Zeiss. In this instrument all the above 

* Journ. B.M.S., 1897, pp. 599-600. 
t Ibid., 1903, p. 85, Fig. 3. 

X I am indebted to Mr. Rousselet for kindly bringing the Ives binocular 
to my notice. 

Journ. B.M.S., 1914, p. 5. 
|| 1911, Vol. 94, No. 2432. 



370 E. M. NELSON ON BINOCULAR MICROSCOPES. 

four attributes of binocular vision are secured. In tins micro- 
scops the left-hand view of the objective is sent into the left 
eye, and the right-hand view into the right eye; this, because 
of the erection of the image, gives an ortho-stereoscopic image. 
If the microscope had been of the ordinary inverting type the 
image would have been pseudo-stereoscopic. It was due to 
ignorance of this principle that several of the early bino- 
culars were pseudo-stereoscopes. One of the most important 
points in this, as well as in all forms of binoculars, is that 
the images should be accurately superimposed. Several tests 
have been proposed ; one was that an object should be 
placed upon the stage, so that it should just touch, say, the 
right edge of the field of the right-hand eye-piece. This eye- 
piece is then transferred to the left-hand tube, and if the object 
still touches the same portion of the field with the same eye- 
piece the adjustment was supposed to be correct. But this 
is no test at all, for it tells you nothing about the really 
important question, which is whether the discs of the fields 
are themselves superimposed. 

The best test for a Greenough is to oscillate rapidly a strip 
of card half-inch wide before the fronts of the objectives. If 
the images shake, then they are not accurately superimposed, 
and the objectives require readjusting in their seats. 

Leaving now the twin microscope, we will pass on to the 
other kind of binocular, which has only one objective. In the 
Wenham this important adjustment is performed by the align- 
ment of the tubes, for the tilt of the prism has very little 
effect, but its edge must be carefully set at right angles to 
a line joining the centres of the eye-pieces. 

The single objective binocular may be divided into two kinds, 
viz. those of the Wenham or Stephenson type, which split the 
beam at the back of the objective, and those of the Fowell type, 
which pass the whole beam. All those of the Wenham type 
possess the first of the attributes enumerated above, viz. stereo- 
scopic effect, for in an ordinary inverting microscope, at the 
left-hand eye-piece the Ramsden disc will be a miniature of 
a cross-section of the beam issuing from the right-hand half 
of the objective, and that at the right-hand eye-piece from the 
left-hand half of the objective, the inversion of the image 
necessitating a cross-over of the pencils, for if there were no 



E. M. NELSON ON BINOCULAR MICROSCOPES. 371 

cross-over the image would be pseudo- stereoscopic. There is 
no cross-over in a Stephenson, but then it is an erecting 
microscope. 

The binocular of the Powell type, which passes the whole 
pencil, does not possess the first attribute of stereoscopism : the 
image in both eyes being identically the same. No doubt, 
owing to the employment of both eyes and for physiological 
reasons, there may be more or less of a stereoscopic effect, but 
that is an entirely different thing from true stereoscopism. 
When, for example, the full moon is observed through a field- 
glass it appears as spherical as a cricket-ball, the images in 
each eye must be identical and no true stereoscopism can be 
present. 

If half the Kamsden's disc above the eye-lens is stopped out 
by a diaphragm, so long as the cross-over is preserved, the 
image in an inverting microscope will be ortho-stereoscopic. This 
was mentioned by "Wenham in 1854; and later, in 1882, Dr. 
Mercer pointed out that a diaphragm is not needed, but an 
ortho-stereoscopic effect may be obtained by making the inter- 
ocular distance less than the interpupillary, which causes the 
iris of the pupil of the eye to cut off the inner half of the 
Ramsden disc. 

The disadvantage of a diaphragm above the eye-piece is that 
it occupies the same place as that in which the eye ought to be; 
and the disadvantage of Dr. Mercer's method is that the head 
and eyes must be kept absolutely steady, otherwise there will be 
a flickering of the image, which causes strain and distress to 
the eyes : the higher the power, the smaller the Kamsden disc 
and the greater will be the flickering and strain and fatigue 
to the eyes. For these causes ortho-stereoscopism in a binocular 
of the Powell type is of a different character from that of the 
Wenham or Stephenson type. In books dealing with this 
subject the Wenham super-eye-piece diaphragm and the Mercer 
narrow inter-ocular distance are treated as alternative plans, 
equal in efficiency to the Wenham divided objective method. 
Such, however, is not the case. It is only necessary to place 
two microscopes alongside each other, charged with similar 
objectives and powers, one having a Wenham divided objective 
and the other a Mercer narrowed inter-ocular distance, when 
an examination of the same object will at once dispel any theory 



372 E. M. NELSON ON BINOCULAR MICROSCOPES. 

as to the equality of the results, the ortho-stereoscopism in 
the Wenham being superior to that in the other. 

In the Wenham and Stephenson, ortho-stereoscopism is weak 
with objectives which have less than 20 of angular aperture (say 
1^ inch of *17 N.A.), and the divided objective breaks down with 
high powers. A divided objective binocular may be said to be at 
its best with a \ inch ; good with 1 inch, |, T 4 (j-, and g ; fair with \ ; 
but failing with a 4. Very small Wenham prisms have been 
made and mounted on a funnel and placed in the mounts of a 
Y2- ', the result being so indifferent that further experiments 
in that direction were abandoned. 

The Wenham plan possesses a great advantage over all other 
kinds of stereoscopic binoculars, viz. that the straight tube is 
free from glasses, prisms, or other appliances likely to disturb the 
image. You will naturally ask, Why then was -the Powell non- 
stereoscopic system introduced ? The answer is that it was 
intended to come in where the W'enham left off, for Powell 
engraved on his Wenham prism, " For Low Powers," and on his 
own prism, " For High Powers." The reason why the high-power 
prism fell into disuse was on account of the poor definition that 
could be obtained with it. It bad no clear tube like the Wenham, 
and it should be remembered that prisms and flat glass surfaces, 
owing to the manufacture of prism field-glasses, are now made 
with a precision and accuracy altogether unknown in 1865, when 
Powell made his. 

Binoculars of the Wenham or divided lens type have the dis- 
advantage of indifferent definition of objects placed vertically 
in the field. If, for example, that well-known test for medium 
powers, the hair of the Polyxenus lagurus, be placed vertically in 
the Wenham, with, say, a one-third objective, the definition 
will be fuzzy ; but directly the hair is placed horizontally in the 
field, the image becomes sharp. In ordinary work with a 
Wenham, where an ortho-stereoscopic image is of primary im- 
portance, this defect is not noticed, and probably only a few 
raicroscopists are acquainted with it. But with the Powell type 
of binocular, this error does not exist. The image is the same 
in all azimuths. Now, in the Wenham high-power binocular, 
which was introduced in reply to Powell's, the beam was divided 
by two right-angled prisms with an air-space between tbem, the 
inclination of the surfaces being adjusted near to the critical 



E. M. NELSON ON BINOCULAR MICROSCOPES. 373 

angle so that some of the light was passed while some was 
reflected. As this took place at both surfaces a double image 
was made in one tube, which, of course, was fatal to the design, 
and the binocular never came into use. Prof. Abbe's binocular 
eye-piece was made on a similar plan and failed for the same 
reason. Subsequently, however, a method was discovered for 
depositing a semi-translucent film of silver on glass, by which 
means a beam could be half reflected and half transmitted. This 
method was adopted by Ives, and the doubling of the image in the 
one tube was avoided. The Ives binocular resembled the Wenham, 
inasmuch as the prism could be withdrawn and the instrument 
used as a monocular. But it also differed from it, for in the 
Wenham the inter-ocular distance was adjusted by lengthening 
or shortening the draw-tubes, while in the Ives it was accom- 
plished by a lateral displacement of the side tube in arc, the 
lower end of this tube being pivoted on a hinge. This was 
a good design, for it permitted the inter-ocular distance to be 
adjusted without disturbing the tube length. In 1860, when the 
Wenham was first introduced, low powers, with their double 
fronts, were very insensible to alteration of tube length, and as 
all powers higher than a | had correction collars, any alteration 
of tube length was of no moment ; this, however, no longer 
applies, because objectives now made with single fronts having 
over-corrected backs are very sensitive to tube length. So in 
designing a binocular for use with such objectives, particular 
attention must be given to tube-length adjustment. 

Now, lately, Messrs. Leitz have brought out a new binocular of 
the Powell type ; the arrangement of the prisms, which deflect the 
rays right and left, differs from the many kinds that have been 
invented for this purpose. The semi- translucent silver film 
method has been adopted by Messrs. Leitz in their new binocular, 
and an almost equally illuminated image is seen in each tube. 
By means of their very perfect system of working prisms they 
have secured a really sharp critical image in each tube. The 
tubes are parallel to one another, but the instrument cannot be 
used as a monocular, for neither body is in the optic axis of the 
objective. Messrs. Beck have also brought out a binocular 
microscope with the two Ives prisms joined in one. The bodies 
are converging, but as one body is in the optic axis of the 
instrument, it can be used as a monocular. 



374 E. M. NELSON ON BINOCULAR MICROSCOPES. 

A great deal has been made of the difference between parallel 
and converging tubes. It has been urged that parallel tubes are 
conducive of eye strain and fatigue. Having now had a Leitz 
microscope in constant use for nearly three months, and having 
done prolonged work with it, no more eye-strain has been found 
with the parallel tubes than with a Wenham, and with both 
there is less fatigue than with a monocular. 

To me the image plane in a microscope appears at so definite 
a distance that I seem able to hold a pencil in front of it, or 
behind it, or touching it. When using a binocular I simply look 
at the image in this plane, being quite as unconscious of either 
the parallelism or convergence of the eyes as if I were looking at 
various objects in the room, or on the table. During the course 
of these experiments several curious observations were made. 
Various persons were asked to examine the images in the Wenham 
and in the Leitz for the purpose of ascertaining their opinion as 





W M 

Fig. 5, 

to the relative amount of stereoscopic effect in each. Two persons 
having good normal vision saw no stereoscopic effect in either, 
the images in both instruments appearing quite flat ; one of them 
could see no stereoscopic effect either in an ordinary stereoscope 
or in a field glass. Two others saw stereoscopism in the Wenham, 
but not in the Leitz with the Mercer method. With the same 
object and same power in both (| inch and B eye-piece), most 
persons said that stereoscopism was stronger in the Wenham, 
owing probably to want of practice and experience with the 
Mercer method. 

When the inter-ocular distance in the new binocular is kept 
of the same width as the inter-pupillary, the microscope is a 
non-stereoscopic binocular. The Mercer plan of reducing the 
inter-ocular distance is found to produce fatigue on account of 
the flickering of the image when the Ramsden disc is small. 

Figure 5 shows the reason why eye strain and fatigue, 
which are present with the Mercer method, are absent with 



E. M. NELSON ON BINOCULAR MICROSCOPES. 375 

the Wenhani ; the circles in W and M represent the pupil of 
the eye, the semi-circle in W is the Ramsden disc in a Wenham, 
and the portion of the circle in M is the Ramsden disc when 
the inter-ocular distance is less than the inter-pupillary in the 
Mercer method. It can at once be seen that a slight movement 
of the head will not affect the luminosity in W, but in M the 
head cannot be moved in the slightest degree without either 
increasing or diminishing the amount of the Ramsden disc 
cut off by the iris of the pupil ; necessarily, therefore, if in one 
eye the Ramsden disc is enlarged it is cut off in the other eye, 
and vice versa, which is the cause of the nickering previously 
mentioned. A moment's consideration will show how this defect 
in the Mercer method may to a certain extent be minimised. 
Obviously the larger the Ramsden disc the less noticeable will be 
this defect. This, of course, points to the use of a low-power 
eye-piece with any given objective. The low-power eye -piece 
has an additional advantage -viz. that the rays emerge at a 
smaller angle than in the case of a deep eye-piece, and this 
permits the eye being held at a little distance from the proper 
eye-point, where the Ramsden disc is expanded. Hence the 
rule for stereoscopism with the new binocular is to make the 
inter-ocular distance somewhat less than the inter-pupillary, and 
not to use eye-pieces deeper than 1| inches, and to hold the eye 
a little way behind the eye-point. 

There are two other sources of eye strain and fatigue common 
to all binoculars of whatever type : the first is non -coincidence 
of the superimposed fields. This by no means uncommon fault 
is due to carelessness in fitting and putting together ; it is a 
source of great eye strain and fatigue, and the purchaser of a 
binocular microscope should be particular to see that the fields 
are precisely superimposed. The second is a difference of foci 
in the tubes. In the binoculars both of Messrs. Leitz and Beck 
provision is made for this by a focusing arrangement in one of 
the eye-tubes. In the Greenough it is accomplished by means 
of a focusing adjustment in one of the objectives. If, therefore, 
a microscope is provided with some such arrangement, the user 
need not be troubled about this point. 

Passing on now to the second attribute of a binocular viz. 
that of increased apparent magnifying power, it is found to be 
as obvious in a microscope as it is in a field glass. Its precise 



376 E. M. NELSON ON BINOCULAR MICROSCOPES. 

amount is difficult to determine, nor is it known if it is the 
same for all persons. As I pointed out elsewhere, it is inaccurate 
to say that there is an increase of apparent magnification in a 
binocular ; what really takes place is that in a monocular there 
is a diminution of apparent magnifying power, and that this dimi- 
nution is non-existent in a binocular. If any one examines a 
lighthouse, a ship, or other object with a 2 or 3 power monocular 
telescope, the image appears no larger than when it is seen with 
the naked eye. The image, as any one will tell you, is brighter 
and clearer, but not larger. Directly the image seen in the 
telescope is superimposed on that seen with the other eye the 
magnification of the monocular is demonstrated, which generally 
causes surprise. Having given this subject considerable attention, 
I am of opinion that the true magnification is seen in a binocular, 
but that with a monocular, either telescope or microscope, this 
is reduced. 

The third attribute viz. illumination : It is doubtful if there 
is much gain in the Greenough type of binocular, as the amount 
gained by the use of both eyes is probably lost owing to 
the prisms, surface reflections, etc. Of course, with a single 
objective type of instrument there must be a loss. This is of 
no importance, for in a microscope one has usually more light 
than is needed. 

The fourth attribute : Experiments have shown that colour 
tints are increased in a binocular ; this is a distinct gain, for 
there is always much and often total loss of colour in micro- 
scopical observations. 

There is another form of binocular which must be mentioned, 
viz. the binocular eye-piece. This was an early invention of 
Wenham ; the next to take it up was Tolles, of Boston, U.S.A., 
who made a very good one by using prisms on the Nachet 
plan, dividing the beam by means of an isosceles prism. Tolles' 
binocular was well made, stood deep eye-pieces, and had the 
advantage that both tubes were similar ; consequently the illumi- 
nation and path of the rays was equal in each. The advantage 
this system possesses is that it permits of objective correction by 
draw tube. With other binoculars objective correction is not so 
easily accomplished. 

The last form of binocular eye-piece was brought out by 
Professor Abbe. This, as we have seen above, was a failure. 



E. If. NELSON ON BINOCULAR MICROSCOPES. 377 

There was another objection, viz. that the path of the rays was 
much longer in one tube than in the other, so that two different 
forms of eye-pieces had to be used. Very few were made, and 
it is probable that no more will be. 

In conclusion let us examine the position of these new 
binoculars. From what has been said above they are clearly a 
class by themselves. It would be quite inaccurate to entertain 
the idea that these instruments are a new kind of stereoscopic 
binocular constructed to enter into competition with, and finally 
to supersede, the existing binoculars of the Wenham and 
Stephenson types ; for from what we have seen they only possess 
the first attribute, viz. stereoscopism in a limited manner. The 
word "limited" is used in default of a better expression. It 
does not mean that with the Mercer effect stereoscopism becomes 
less strong, for, on the contrary, with the Mercer effect hyper- 
stereoscopism is often present, and care should always be taken 
to guard against it. With the Mercer effect a cell, for example, 
which is, and which under a Wenham would look, like an 
ellipsoidal football will appear under a hyper-stereoscopic Mercer 
effect as if standing on end. 

The centre of that beautiful diatom, plentiful on " Mud 
Cuxhaven " slides, viz. Actinocyclus Ralfsii, under hyper-stereo- 
scopism appears at the bottom of a deep pit, the outer annulus 
being highly raised,* whereas we know that the structure is a 
kind of shallow saucer. The word "limited" is intended to 
apply to the stereoscopic condition that the Itamsden disc cannot 
be centred to the pupil. The Mercer plan also entails loss of 
light and of resolution of vertical striae. Messrs. Leitz provide 
their inter-ocular adjustment with a millimetre scale. The 
observer should carefully note the precise adjustment that will 
centre the Ramsden disc to his own eyes ; half a division on the 
scale (which represents 1 mm.) or even less ought to suffice for 
the Mercer effect. The test of coincidence of the inter-ocular 
with the inter-pupillary distance is that of maximum brightness. 
Luminosity quickly falls off with either increase or decrease of 
inter-ocular distance. With a little practice, one becomes so 
expert in judging the luminosity that a reference to the divided 
scale is seldom necessary. 

* Seen best with transmitted light, a No. i objective and a 1 inch 
eye-piece. 



378 E. M. NELSON ON BINOCULAR MICROSCOPES. 

You will then naturally ask, If these new binoculars are not 
stereoscopic, what is their use? Their use is confined to the 
employment of full Kamsden discs in each eye, that is for 
work with non-stereoscopic images. An enormous amount of 
microscopic work is done with images of that kind, and when 
prolonged work is undertaken with the new binocular great 
relief and comfort to the eyes will be secured. But to say, on 
the one hand, that one of these instruments when used for, 
say, the examination of pond life with a \ inch and the Mercer 
effect is going to supersede a Wenham, and on the other hand 
to state that by means of this new binocular delicate secondary 
structures on diatoms will be more easily seen than with a 
monocular, is to talk nonsense. At the upper limit they cannot 
compete with the monocular, and at the lowest limit they cannot 
compete with the Wenham ; but in their own sphere they are 
extremely useful and form a very important addition to the 
modern improvements in Microscopy. 

At any time with the new binocular the Mercer effect can be 
turned on to determine the relation of the various parts of an 
object ; but it must be borne in mind that stereoscopism in a 
microscope with the higher powers is only partial, and whether 
it is present or not depends largely upon the nature of the 
object; for example, with a medium power, such as \ or a 
i, the rays of a Heliopelta will exhibit strong stereoscopism, 
but many other objects with the same power will show none. 
With a \ and a spread slide of P. angulatum, it is difficult to 
determine whether a valve is convex or concave side up. Stereo- 
scopism in macroscopic vision differs from that in microscopic 
vision inasmuch as it is influenced greatly by the thickness of 
the object. 

With macroscopic vision stereoscopism is seen equally well 
with either a book or a bookcase, but that is not so with 
microscopic vision. In that case stereoscopism would be present 
with our allegorical bookcase but not with the book. Low 
powers deal with thick, coarse objects, and therefore stereoscopism 
is present ; but with the higher powers it is necessary to select 
suitable objects for the demonstration of the stereoscopic effect. 
For instance, bacteria dried on cover do not exhibit any more 
stereoscopism with the new binocular than with a monocular, 
for in a monocular they can be made to look like sausages ; but 



E. M. NELSON ON BINOCULAR MICROSCOPES. 379 

when bacilli in tissue are examined with the Leitz binocular, a 
^ and the Mercer method, a beautiful picture of them in 
perspective projection will be seen as well as of the cell nuclei 
which appear spherical as marbles. 

It is a good plan when working with this new binocular to 
turn on the Mercer effect and when the form of the image has 
been mentally grasped to turn it either wholly or partly off, 
for when the stereoscopic form of an object has once been 
realised by the mind re can be retained, although the optical 
conditions which gave rise to it have been removed. Some will 
have noticed, when looking at parquetry representing cubes, that 
if the effect when first noticed is intaglio it is a matter of some 
difficulty to reverse this mental image so that the cubes shall 
appear to be in alto-rilievo. 

I asked Messrs. Leitz to make me a couple of tubes to slide 
over their tubes, by which means tube-length adjustment can 
be accomplished. The tubes can be drawn up and down over 
the fixed tubes and the eye-pieces also can be partially drawn 
out, as the tubes are sprung both top and bottom. Without 
these tubes it was not possible to obtain a critical image with 
Messrs. Leitz' own objectives for the Continental short tube. 

The great charm in these new binoculars consists in the 
sharpness of the image combined with ease and comfort of vision, 
hence the need for lens correction either by alteration of tube 
or by screw collar. The sharpness of image in my instrument 
at least is very little behind that of a monocular, for it requires 
a delicate test to perceive any difference at all, and often a pair 
of 18 compensating eye-pieces have been used with advantage. 

With a ^ inch objective and upwards, these new binoculars 
have the field all to themselves, as no other binocular for sharp- 
ness and crispness of image can for a moment compete with 
them. With low powers and 1^ inch eye-pieces and a slight 
Mercer effect they give lovely images, but, as was hinted above, 
with the Mercer effect one must alwaj^s be on one's guard against 
hyper-stereoscopism. Recently a shock was experienced on finding 
that a Radiolarian which appeared under the Mercer effect as 
round as an orange, when viewed on edge was shaped rather like 
a mince pie. Here the Wenham gave the truer image. 

Latterry, even the Greenough, which is known to give beautiful 
images, has been suspected of hyper-stereoscopic tendencies. 

Journ. Q. M. C, Series II. No. 75. 27 



380 E. M. NELSON ON BINOCULAR MICROSCOPES. 

I never expected to live to see a critical image of a Podura 
scale in a binocular, but that is now an accomplished fact, for I 
have seen a most beautiful picture of a Podura scale with the 
Leitz binocular and an apo 4 mm., and that, too, critical in all 
azimuths. 

Dark-ground images are very suitable for the new binoculars 
because the objective is working at full cone, so there is a larger 
Ramsden disc than would be usually the case with transmitted 
light. 

Messrs. Leitz sent with the microscope some of their new 
Orthoskop-Kellner eye-pieces, the performance of which is very 
satisfactory. I have had a cap, attachable to the eye-piece by a 
small screw, made to prevent the eye lens being smeared by 
contact with the eye-ball. This with a binocular happens 
frequently, so that a process of continual wiping of the eye-lens 
is necessary, which causes interruption and much interference 
with one's work. 



Journ. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 75, November 1914. 



38] 



NOTES ON THE CULTIVATION OF PLASMODIA OF 

BAD HAM I A UTRICULARIS. 

By A. E. Hilton. 

{Head May 26*A, 1914.) 

Fig. 6. 

A free-flowing mass of naked and almost undifferentiated 
protoplasm, such as we have in the plasmodium of Badhamia 
utricularis, suggests opportunities for biological experiments, 
with unusual promise of success. From living matter in so 
primitive a condition, it should be possible, one imagines, to gain 
a more intimate knowledge of the fundamental substance which 
is the basis of all physical life. 

Systematic investigations, however, depend upon a constant 
supply of material, and a continuous supply of plasmodia is not 
easy to obtain. In natural surroundings, they are only to be 
found when conditions of temperature and moisture are suitable ; 
and even then, in most districts, they are very scarce. More- 
over, the removal of a plasmodium to a place suitable for 
studying it, generally results in the plasmodium shortly passing 
into the sporangial stage, or perishing from lack of proper 
nutriment. Either way, the immediate end is defeated. 

In the Introduction to Mr. Lister's Monograph of the 
Mycetozoa, recently revised by his daughter, it is stated that 
" The plasmodium of Badhamia utricularis is one of the very few 
we are acquainted with that feed on living fungi," and that " it 
is capable of being cultivated without limit on Stereum hirsutum 
and allied species, and can be observed under the microscope to 
dissolve fungus hyphae as the hyaline border of a wave of the 
yellow plasmodium advances over them." In many places, 
however, an unfailing stock of the fungus mentioned is difficult 
to ensure ; so that here, again, a difficulty arises. 



382 A. E. HILTON ON NOTES ON THE CULTIVATION OF 

Professor De Bary (1884), in his great work on the Com- 
parative Morphology and Biology of the Fungi, Mycetozoa and 
Bacteria, mentions boiled cabbage leaves as having been used for 
the cultivation of Mycetozoa ; but he does not name the species 
which were cultivated, and boiled cabbage leaves, if kept for any 
length of time, become too offensive for endurance. 

In 1906, an account was published in Germany of experiments 
in the cultivation of plasmodia made by J. G. Constantineau ; 
and these are alluded to both in Mr. Lister's Monograph and 
the Royal Microscopical Society's Journal for April 1907. In 
neither of these are details given, or any indication of the 
extent to which the experiments were successful. Possibly 
they were too technical to be of general use. ' 

No apology, therefore, is needed for placing on record the 
result of experiments made during the last few months, which 
suggest a method of continuous cultivation of plasmodia of 
Badhamia utricularis, at once simple and practicable. Whether 
this method, with or without modification, is applicable to 
plasmodia of other species, I have not had an opportunity of 
<letermining. Other workers may perhaps take up the suggestion 
and carry the matter further. 

In the first place, I have found that the growth of a Plas- 
modium of B. utricularis can be stimulated by the occasional 
application of a mixture of ammonium phosphate * and cane 
sugar, half an ounce of the phosphate and the same weight of 
sugar being dissolved in a quart of water. 

In the second place, I find that the plasmodium will feed and 
grow on bread kept moistened with water, especially if some of 
the mixture described be added to it from time to time. 

The effect of the mixture seems to be both direct and indirect- 
It appears to impart greater vigour to the plasmodium, so 
increasing its feeding capacity ; and it also benefits the plas- 

* Since the above paper was read, Mr. James Grundy has informed mc 
be has added calcium phosphate to the mixture with excellent results. 



PLASMODIA OF BADI1AMIA UTRICULARIS. 383 

m odium indirectly by promoting the growth of filamentous 
moulds, such as Aspergillus or Penicillium, which soon appear on 
fungus or bread, after the mixture has been applied to it. The 
hyphae of these moulds are dissolved and absorbed by the proto- 
plasm as food. 

In using the mixture discretion must be exercised, according to 
the condition of the plasmodium, as sometimes plain water is 
preferable ; but the careful observer will find sufficient indications 
to guide him in this respect. No precise rules can be laid down, 
but the student will find that with these auxiliary helps he will 
be less dependent than heretofore on a supply of Stereum or 
similar fungus, although it may be advisable to use some of that 
at times, if convenient, as being the more natural food. Any 
fungus which becomes putrid must be removed, or it may poison 
the plasmodium ; but the bread is not so liable to become 
injurious, and may remain a reservoir of protoplasm until, after 
a prolonged period, the plasmodium has eaten it all. 

]STote. I have also been asked to describe, for the benefit of 
our readers, my method of exhibiting the reversing currents of 
streaming plasmodia, a description of which has been given in 
the Journal.* The very simple arrangement is shown in the 
diagram below. 






Fig. 6. 

A tube of this size is sufficient, and a ring of blotting-paper, 
with sclerotium upon it, is placed inside ; the sclerotium being 
between the paper and the glass. A few drops of water are 
added, the cork is inserted, and the tube is then tilted and 
revolved until the water has soaked the paper and moistened the 

* Joum. Q.M.C., Vol. X., pp. 263-270, November 1908. 



384 A. E. HILTON ON PLASMODIA OF BADHAMIA UTRICULARIS. 

whole of the interior surface of the tube. A small hole is bored 
through the cork to admit air without allowing too much 
evaporation ; or the cork may occasionally be removed. If 
necessary, a drop or two of water can be added now and then, to 
keep the air moist. Only plain water should be used. When 
the sclerotium revives, the plasmodium creeps on to the glass on 
either side of the ring of paper, and the reversing currents can 
then be seen by placing the tube on the stage of the microscope 
and throwing the light up through it from the mirror beneath. 
A 1 inch objective, focused on the veins of the spreading 
plasmodium, shows the streaming movements quite plainly. The 
sclerotium should be placed in the tube the day before the 
plasmodium is required for exhibition. 



Joarn. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 75, November 1014. 



on K 



85 



ON THE MINIMUM VISIBLE. 

By A. A. C. Eliot Merlin, F.R.M.S. 

(Read October 27th, 1914.) 

I have read with great interest and profit our President's 
Address on " Organisms and Origins." The subject is one that 
must fascinate every microscopist, whatever his line of research 
may be. In the address a point was raised respecting the 
minimum visible, it being stated that " it seems impossible to 
obtain any precise information as to the size of the smallest 
particles that can be seen with the microscope." 

Now, setting aside the ultra-microscope, as our knowledge is 
very exact and definite indeed on this subject, it may prove of 
interest to deal with the question at some length. As a matter 
of fact, when a particle properly illuminated is just visible under 
a given objective, if the aperture be cut down by means of an iris 
diaphragm placed above the back lens so that the particle just 
ceases to be visible, and the numerical aperture to which the 
objective has been thus reduced is measured, then the dimensions 
of the particle can be exactly ascertained from the antipoint table 
published by Mr. Nelson in the Journal of the Royal Microscopical 
Society. This antipoint table should prove invaluable when 
accurate and minute measurements are necessary, but little 
interest has been apparently evinced in the matter since micro- 
metry of a high order is no longer practised, in England at least. 
Leaving this for the present, I venture to refer to and examine 
the claim made by Mr. Brown at a recent meeting of the Club 
that he had seen central " pores " on the surface of the frustules 
of certain diatoms ; which he estimated at l/200,000th of an inch 
in diameter. On reading Mr. Brown's " Notes on the Structure 
of Diatoms," * I examined a specimen of Pleurosigma balticum, 

* Journ. Q.M.C., Ser. 2, Vol. II. p. 317. 



386 A. A. C. ELIOT MERLIN ON THE MINIMUM VISIBLE 

in realgar, under a very perfect recent 1/1 2th apochromat of 
N.A. 1*4, employed with a magnification of 4,200. Mr. Brown's 
central "pores" could be readily distinguished at a certain high 
focus on the outer layer of the valve. But in the " pores " so 
revealed I immediately recognised my old friends Dr. Boyston- 
Pigott's " dark eidolic dots of interference." In thus frankly 
stating my conviction, I am sure that Mr. Brown, as a veteran 
observer, would wish me to pursue no other course. We are all 
liable to make mistakes in the interpretation of diatomic struc- 
ture, and the only hope of progress lies in friendly criticism and 
the exchange of views. Although I consider Mr. Brown's central 
" pores " of Pleurosigma balticum, Navicula serians and P. angu- 
lation! to be clearly false ghosts, it is by no means unlikely that 
the outer layers of these diatoms may be perforated with fine 
secondary structure, like the forms with coarser primaries. 
Under the most critical conditions, with T4 N.A. and a magnifi- 
cation of 4,200, something of the kind has been seen both in 
P. balticum and N. serians. These appearances, however, are 
far more elusive and difficult than the eidolic central clots, and 
quite different in aspect and position. So far as my experience 
goes, capped diatomic primaries are always pierced by at least 
three or four secondaries when any such structure is observable. 
It may nevertheless be safely asserted that if the primaries of 
P. angulatum are thus capped and pierced, the secondaries must 
be as much beyond the grasp of our best lenses as are the eidolic 
dots of A . pellucida. 

In order to show how similar are the observational conditions 
described by Dr. Royston-Pigott as necessary for the proper 
demonstration of eidolic clots to those specified by Mr. Brown 
concerning his central diatomic " pores," I must quote Dr. Royston- 
Pigott's remarks on the subject at some length. In "Micro- 
scopical Advances " * it is stated : " With regard to attenuated 
circles, nothing are more abundant in diatomic and scale 
markings. If a spherule be l/60,000th of an inch, the black 
marginal ring is generally about one-fifth of this, or 1 /300,000th 
thick, ornamented with a minute central black clot. The clot and 
its fellows are amongst the most interesting and surprising sights 
in minute microscopy. Few glasses will show them. That a 

* English Mechanic, vol. xlviii. p. 209. 



A. A. C. ELIOT MERLIN ON THE MINIMUM VISIBLE. 387 

minute spherule should be capable of exhibiting the same 
recherchcs phenomena as a delicate glass lens l/30th focus solely 
from its refractions and chromatic aberrations, at first seems 
quite incredible." In another place * Dr. Poyston-Pigott con- 
tinues : " The existence of dark eidolic dots of interference is an 
important fact which now requires further elucidation. Darkness 
has resulted from excessive light. Wave neutralising wave, certain 
undulations killed each other. This is seen on a grand scale in 
the solar spectra formed by a small lens in the foci of a very fine 
microscojDe. Forty-eight dark rings have been counted developed 
by an extremely small solar beam. The feeble refractions occur- 
ring in a diatomic convexity cannot develop a very numerous 
retinue of rings ; but sufficient diatomic lenses have been accumu- 
lated for the purpose indicated. To exhibit successfully a series 
of eidolic dots of interference demands very careful illumination 
and a very fine objective. Their size varies with the nature and 
diameter of the refracting spherule. The 1/Sth water lens of 
Powell and Lealand seems to excel all my others in detecting 
them in different focal planes. Six have been in order thus seen, 
but in small spherules such as those of P. angtdatum many dots 
are too faint for recognition. My experience of scale molecules 
has convinced me they also are wonderfully transparent, display 
black marginal test rings, and often one eidolic dot." . . . " These 
dots are well developed by large beading of diatoms from 1/9, 000th 
to 1/1 4,000th of an inch in diameter. Extremely large spherical 
beads are seen in Cresswellia superba and in Cestodiscus superbus 
(beads 1/1 2,500th) ; E. costatus and C oscinodisens radiatus are 
also fine examples. To exhibit successfully all the eidolic dots of 
interference in successive focal planes demands very excellent 
glasses, careful precautions, and, above all, well-separated diatomic 
beads. They may be caught above very small diatomic and scale 
beading. Remarkably good eyesight has distinguished them 
above the bosses of P. angulation and occasionally I have 
detected two sets of dots when one stratum of beading lies just 
below another. In general, except in strongly pronounced 
diatomic bosses, the observer may rest satisfied with finding the 
primary eidolic dot, No. 1, fig. 1 in the diagram. f A better glass 

* English Mechanic, vol. xlix. p. 315. 

t A diagram showing a series of eight gradually diminishing dots is 
annexed to the original paper. 



388 A. A. C. ELIOT MERLIN ON THE MINIMUM VISIBLE. 

may enable him to detect Nos. 2 and 3 by daylight. Lamplight, 
unless its yellow tint be subdued with a blue chimney and other 
blue glasses, extinguishes the dot by the flame image produced by 
the diatomic lens. It may be recovered, however, in front of it 
by careful manipulation." ..." Dr. Van Heurck obligingly 
photographed with the new apochromatic glass the eidolic dot 
shown by the beading of P. angulatum." 

Dr. Royston-Pigott estimates the dots in P. angulatum to be 
attenuated to 1 /250,000th of an inch and considers that 
extremely minute dots, about 1/300, 000th, are not only found 
amongst diatoms, but reveal themselves in the transparent 
headings of moth-scales, and adds, " but there are many forms 
of these dots." It is also remarked that " exquisitely small and 
black dots can often be seen in focal planes elevated slightly 
above diatomic beads by using a black central stop below the 
condenser. It requires very grand glasses to display these elegant 
results." It is needless to point out that the late Dr. Royston- 
Pigott was an upholder of the now abandoned view that the 
perforations of diatoms were solid silex beads or bosses. The 
foregoing sufficiently proves that the central eidolic dots or 
" pores " of diatoms were well known twenty-six years ago, but 
those specially interested in the subject should read the papers 
referred to. 

Setting aside all such diffraction phenomena, or false ghosts, 
probably the most delicate, true diatomic structures just within 
the grasp of our finest modern objectives of large aperture are 
the thin perforated " veils "' to be detected on certain diatoms. 
Of these perhaps one of the best examples is Triceratium america- 
nitm, var., Oamaru, mounted in styrax by M oiler. It is a difficult 
structure with axial screen illumination, but there can be little or 
no doubt that the appearances observable represent real perfora- 
tions in a thin outer plate. In this diatom there is no complicated 
structure to bewilder the observer and manufacture false ghosts. 
It is, however, extremely improbable that the minute perforations 
of the IViceratium americanum, difficult as they are, represent 
anything smaller than the 1/1 00,000th of an inch, and being 
subject to the limitations of the laws of diffraction, like 
all periodic structures, are consequently of little help as 
an example of the minimum visible under more favourable 
conditions. 



A. A. C. ELIOT MERLIN ON THE MINIMUM VISIBLE. 389 

In biological investigations it is frequently required to view 
widely scattered living particles, or germs, of various sizes down 
to the most minute dot that can just be detected. When any 
such particle is under observation nothing is easier than to 
measure its dimensions accurately by the anti point method. 
There is in my cabinet a section of fluor spar, given to me by 
Mr. Traviss, which contains numerous liquid-filled cavities of 
various sizes. In each cavity there is a rapidly moving bubble. 
Some of these bubbles, under a 1/1 2th apochromat of 1*4KA., 
appear as mere trembling specks only just visible and within the 
grip of the objective, and there are probably others too minute 
to be seen at all. Selecting a bubble just visible under such 
conditions when illuminated with a large axial cone and Gifford 
screen, if we wish to ascertain its diameter we have only to refer 
to Mr. Nelson's papers, "A Micrometric Correction for Minute 
Objects," * and " The Influence of the Antipoint on the Micro- 
scopic Image shown graphically." f These papers contain all 
the necessary explanations and data, and we find from the 
amended table in the latter paper that with a working aperture 
of 1*4 and screen the minimum particle visible must have a 
diameter of 0-00000265 (l/377,358th) in., or 0'0673 /x : the photo- 
graphic limit being with similar aperture 0-00000209 (l/478,4:69th) 
in., or 0'5031 /x. 

Thus we can measure accurately the diameter of the smallest 
particle or bubble visible with a given aperture. The accuracy 
of the result depends on knowing exactly the N.A. employed at 
extinction point, and this must in each case be found with an 
accurate apertometer. It is advisable that the working aperture 
should nearly equal the N.A. of the objective at the extinction 
point, but it need not necessarily be quite full cone. When the 
critical point is reached a very slight decrease of N.A. makes all 
the difference between easy visibility and invisibility. Mr. 
Nelson's first table " was computed by the formula 



5-4686 \ W.A. 
The numerical coefficient was determined from data found by the 

* Journ. R.M.S., 1903, pp. 579-82. 

t Ibid., 1904, pp. 269-71. See also " On the Measurement of Very- 
Minute Microscopical Objects " {Journ. R.M.S., 1909, pp. 549-50). 



390 A. A. C. ELIOT MERLIN ON THE MINIMUM VISIBLE 

extinction of the image of a minute point by reducing the W.A. 
to 0'165. The size of the point was measured by a wide-angled 
oil-immersion, and a W.A. of 0*9, and was found to be apparently 
1/50, 050th inch. From this we have 

6-6961X-165 = 50,050. 
And 

:0-000003663. 



li-6961\-9 



Employing this as a provisional correction, we find the size of the 
point to be 1/4 2,396th in. Again, using this measurement, we 
obtain a new numerical coefficient, viz. 5*6587, and finally find 
the size of the point 1/40, 875th in., and the coefficient 5*4686 as 
stated above. In this calculation A is the reciprocal of the wave- 
length, or the number of waves per inch, given at the head of 
each column in the table." In Mr. Nelson's subsequent paper, 
" The Influence of the Antipoint on the Microscopical Image 
shown graphically," the data will be found for the slightly 
amended table given therein. 

Shortly after the publication of Mr. Nelson's papers on this 
interesting subject, Dr. Coles kindly sent me a well-stained 
balsamed slide of the putrefactive microbe B. termo. On this I 
was able to find a distinctly flagellated specimen suitable for 
measurement by the extinction method. The flagellum could be 
plainly seen with an apochromatic l/6th of 0*98 N.A. used with 
a full cone and screen, and it became invisible when the N.A. 
was gradually cut down to 0*42 by means of an iris diaphragm 
over the top lens of the objective, thus making the diameter of 
the flagellum 0*00000S91 (1/1 1 2,200th) in., or 0*226 fx. 

Afterwards a balsamed-stained, flagellated specimen of the 
tubercle bacillus was found. This was more difficult to see, and 
the flagellum was thought to be much finer than that of the 
B. termo. A 1/8 tli apochromat of 1*4 N.A. was employed to 
measure this. When the N.A. was cut down to the vanishing 
point and tested with the Abbe apertometer, it was found to bv 
exactly 0*42, thus making the diameter of the tubercle bacillus 
flagellum precisely equal to that of the B. termo. It may here 
be mentioned that the existence of the tubercle bacillus flagellum, 
discovered by Mr. Nelson, has been denied. It has, however, 



A. A C. ELIOT MERLIN ON THE MINIMUM VISIBLE. 391 

been observed by many microscopists, including myself, and has 
been beautifully photographed by Mr. Nelson.* 

Now the flagellum of B. termo was most carefully measured 
by the late Dr. Dallinger, and his results were embodied 
in a paper entitled " On the Measurement of the Diameter 
of the Flagella of Bacterium termo : a Contribution to the 
Question of the ' Ultimate Limit of Vision ' with our Present 
Lenses." f Two hundred measurements were made by means of 
a fine pencil mark made over half or two-thirds, not over the 
whole, of the camera-lucida image of the flagellum. The labour 
entailed may be judged from Dr. Dallinger's statement: "Now 
I made fifty separate drawings and measurements with each 
of the four lenses, the same conditions being observed in each 
case. The results expressed in decimal fractions are as follows, 
viz. : 

" 1. The mean value of fifty measurements made with the 
1/1 2th in. objective gives for the diameter of the flagellum 
000000489208. 

" 2. The mean value of fifty measurements made with the 
l/16th in. objective gives 0-00000488673. 

" 3. The mean value of fifty measurements made with the 
l/25th in. objective gives 0-00000488024. 

" 4. The mean value of fifty measurements made with the 
l/35th in. objective gives 0-00000488200. 

" We thus obtain a mean from the whole four sets of measure- 
ments, which gives for the value of the diameter of the flagellum 
of B. termo 0*00000488526, which, expressed in vulgar fractions, 
is equivalent to 1 /204700th of an inch nearly; that is to say. 
within a wholly inappreciable quantity." 

These classical measurements of the diameter of the B. termo 
flagellum are of the greatest importance, for by their means the 
accuracy of the extinction method is demonstrated, which in turn 
serves to confirm the exactness of the late Dr. Dallinger's results. 
Assuming that a W.A. of 8 was employed, the necessary anti- 
point correction by Mr. Nelson's amended table is 0*000005 13th in., 
which,addedtoDr.Dallinger'smean,makes0*00001001(l/99,900th) 
in. for the true diameter of the flagellum, as against 0*00000891 

* Journ. Q.M.C., Ser. 2, Vol. XI. PI. 22. 
f Ibid., 1878, pp. 109-75. 



392 A. A. C. ELIOT MERLIN ON THE MINIMUM VISIBLE. 

(1/1 12,200th) in., the diameter obtained by me from Dr. Coles's 
specimen by extinction measurement. The latter method is 
certainly not second to Dr. Dallinger's in exactness, whileit is 
undoubtedly less laborious. Through no fault of his own, Dr. 
Dallinger's uncorrected figures put the diameter of the flagellum 
at half its true dimensions. 



Journ. Quekett Microtcopical Club, Ser. 2, Vol. XII., No. 75, November 1014. 



39:; 



REMARKS ON TWO SPECIES OF AFRICAN VOLVOX. 

By Charles F. Eousselet, F.R.M.S. 
(Read October 21th, 1914.) 

The slides of two species of African Volvox which I am 
exhibiting to-night have a history of unusual interest. 

It will be remembered that at the meeting of this Club on 
October 25th, 1910, a paper was read by Prof. G. S. West of 
Birmingham University, in which two new species of Volvox 
from Africa were described. 

One of these, Volvox africames, of small size and oblong in 
shape, was found in a Plancton collection made in July 1907 
by Mr. R. T. Leiper, of the Egyptian Government Survey, near 
the northern shores of the Albert Nyanza. I received a very 
small quantity of this collection for the purpose of determining 
the Rotifera it contained, and found these pretty oval colonies of 
Yolvox, as did also Prof. West, who had received a similar 
sample, in order to name the various fresh-water algae 
contained therein. 

The other species is of very much larger size (as much as 
l/20th inch in diam.), of spherical shape and densely crowded with 
cells on its surface (estimated at 50,000 cells in one of the larger 
Colonies), was found by myself on the occasion of the visit of the 
British Association to South Africa in September 1905 at 
Gwaai Station in Rhodesia, about half-way between Bulawayo 
and the Victoria Falls of the Zambesi ; the train stopped for 
half an hour at this station by the side of a shallow pool formed 
by the Gwaai River, and as usual I jumped out of the train with 
my collecting- net and bottle and secured a dip from the pool. 
As the train went on I examined the contents of my bottle, and 
besides various Rotifera I noticed some large colonies of Volvox. 
The whole collection was put up in formalin, and eventually the 
specimens of Volvox were handed over to Prof. West for 
description, which was done in our Journal in November 1910.* 

Of both these African Species of Volvox vegetative colonies 
only had been found, and Prof. West expressed his regret that 
the sexual colonies in various stages were not represented, so 
that his description was necessarily incomplete. 

This closed the first stage of the story. 

In May 1912 Dr. A. W. Jakubski published in the Zoologischer 
Anzeiger a paper on Rotifera collected by him in the Ussangu 
Desert in German East Africa, in which several new species of 
Distyla were figured and described. At that time Mr. James 
Murray was writing papers on the Rotifera of Australasia and 
South America and in particular was studying the family of the 

* Journ. Q.M.C., Ser. 2, Vol. XL, p. 99-104. 



O 



94 C. F. ROUSSELET ON TWO SPECIES OF AFRICAN VOLVOX. 



Cathypnidae, and we considered it very desirable to obtain, 
if possible, specimens of the new species described. So after I 
had ascertained that the author was working at the Zoological 
Institute at Lemberg University I wrote to Dr. Jakubski 
asking him to be good enough to send me a little of the material 
containing the species of Rotifera. Some time in the spring of 
1913 the Doctor very kindly sent a few slides and also about eigh- 
teen tubes of Plancton material collected in German East Africa. 
By this time Mr. James Murray had left England on his way to 
the disastrous North Canadian Arctic Expedition, from which 
he has not returned, and being myself much occupied with other 
work, 1 delayed the examination of this material until the spring 
of the present year, when I received a polite reminder from the 
sender asking for the return of his tubes as soon as convenient. 
This request obliged me to look over the contents of the tubes 
without further delay, which was clone in May and June last. 

In his paper the author states that in deserts of German 
East Africa pools and ponds are rare and can only be found after 
heavy rainfalls, and are then shallow and last a very few weeks 
only, but often develop a considerable amount of Plancton 



organisms. 



In two of the tubes, amongst various Rotifera, I was surprised 
and fortunate to come across numerous colonies of Vol vox 
which I at once recognised as the same two species from 
Africa described by Prof. West four years previously. Moreover 
both species were present in various sexual stages with 
androgonidia and oospores, the male and female colonies, as 
well as the vegetative colonies.* The ripe star-shaped oospores 
of the large Volvox Rousseleti in particular are very fine and 
remarkable, and these specimens will now enable Prof. West 
to describe the complete life- history of both these African species, 
which appear to be widely distributed in that continent, though 
not as yet known from any other part of the world. 

After completing my examination of the material I returned 
all the tubes to Dr. Jakubski at Lemberg in Galicia early in 
July, but have not heard whether they reached him. The 
tragedy of the situation is that at the end of the same month 
war was declared and Lemberg (Lwow) was one of the first 
towns of importance taken and occupied by the Russian army, 
and it is at present impossible to ascertain what has become of 
either my correspondent or his collection of specimens. 

You will agree that it was a piece of extraordinary and 
remarkable good luck that these collections came into my hands 
and at this particular time. 

* Slides were exhibited by Mr. Eousselet showing the various sexual 
stages. 

Joum. Quekctt Microscopical Club, Her. 2, Vol. XII. , No. 75, November 1914. 



395 



REPORT ON THE CONFERENCE OF DELEGATES OF 
CORRESPONDING SOCIETIES (BRITISH ASSOCI- 
ATION) HELD AT HAVRE, 1914, BY INVITATION OF 
THE ASSOCIATION FRANCAISE POUR L'AVANCE- 
MENT DES SCIENCES. 

{Bead October 27th, 1914.) 

To the President and Council of the Quehett Microscopical 
Club, London. 

As your Delegate I attended the Havre Congress of the 
French Association, which began on Monday, July 27th. The 
Opening Meeting was held in the Grand Theatre, where Monsieur 
Armand Gautier, the President, welcomed the members and 
delivered an address. On behalf of the English members 
Sir William Ramsay addressed the meeting in French. In the 
evening there was a reception by the Mayor and Corporation 
in the Town Hall. On the Tuesday I attended a Conference 
of the Delegates of Corresponding Societies in the Town Hall, 
when Sir E. Brabrook read a discourse on behalf of the Chair- 
man, Sir H. G. Fordham, who was absent, " On the History 
of British Association Conferences of the Delegates," of which 
it appears Mr. John Hopkinson was the founder. Mr. Hop- 
kinson read a paper on "Local Natural History Societies and 
their Publications," in which he advocates certain rules in 
the publication of Transactions which would render them more 
easily capable of being referred to and quoted by inquirers 
or the bibliographer, and at the same time save expense in 
making reprints for distribution by the authors. 

Sectional Meetings took place on the Tuesday and Wednesday, 
although clouds were then gathering on the political horizon, and 
some presidents of Sections did not appear. On the Thursday, 
July 30th, the Congress went on an excursion by train and 
boat up the River Seine as far as Rouen, visiting many historical 
places of interest and some famous old and ruined cathedrals 
and ancient Roman settlements, such as Lillebonne, Caudebec, 
Jumieges, La Bouille, on the way. 

On the following day, Friday, more meetings of Sections w T ere 
Journ. Q. M. C., Series II. No. 75. 28 



396 REPORT ON THE CONFERENCE OF DELEGATES HELD AT HAVRE. 

held, but were very poorly attended, as the political outlook was 
more and more threatening and many members were called away 
and left hurriedly. 

On Saturday, August 1st, most presidents and secretaries of 
Sections had gone and only a very few meetings took place. On 
that morning at the Zoological Section I read a short paper 
in French on " Pedalion or Pedalia, a Question of Nomenclature 
in the Class Potifera." About midday a Government announce- 
ment or " Decret " was placarded at the Town Hall and at 
Post Offices ordering a general mobilisation of the French Army,, 
to commence at midnight, when the Congress broke up. 

I left Havre the same night by steamer for Southampton r 
where I arrived on Sunday morning, about three hours late, the 
boat having been held up several times in the Channel by 
torpedo-boats. Thus ended a most tragic meeting of a Congress 
for the Advancement of Science. 

(Signed) Charles F. Pousselet. 



Journ. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 75, November 1914. 



o\n 



PEDALION OU PEDALIA; UNE QUESTION DE 
NOMENCLATURE DANS LA CLASSE DES ROTIFERES. 

Par Charles F. Rousselet. 

[Paper read by the author as the Queliett Club'' a Delegate to the Conference 
of Delegates of Corresponding Societies of the British Association held at 
Havre by invitation of the Association Franqaise pour V Avancement des 
Sciences. Section de Zoologic, Seance du l er A out 1914.] 

Au 6 me Congres de l'Association Frangaise pour l'Avancenient 
des Sciences term au Havre en 18"7 M. Jules Barrois presenta 
un memoire portant le titre: "Sur 1'anatomie et le developpement 
du Pedalia mira." (Seance de la Section de Zoologie du30Aoiit 
1877.) 

Or en 1871 le Dr. C. T. Hudson avait decouvert dans une mare 
d'eau douce a Clifton pres de Bristol un Kotifere extraordinaire, 
ayant six membres arthropodiques, l'un sur la face ventrale, un 
second sur la dorsale, et deux de chaque cote du corps, au moyen 
desquels 1'aniinal peut nager et avance dans l'eau par petits 
sauts, semblables aux mouveruents des larves des crustaces 
Cyclops. Hudson noinma l'animal Pedalion mirum. 

En examinant ces jours le volume des Comptes rendus du 
Congres de 1877 j'y trouve a la page 661 un Extrait de la com- 
munication de Barrois portant le titre ci-dessus. On voit que le 
nom de Pedalion a ete change en celui de Pedalia. En lisant 
plus loin on y trouve les phrases suivantes : 

" M. J. Barrois a ete conduit par ses etudes sur les Bryozoaires 
a considerer la forme primitive de ces animaux comme comparable 
a l'etat adulte des Botiferes. Pour elucider cette question 
M. Barrois a entrepris au laboratoire de Wimereux l'etude de 
l'embryogenie du genre Pedalion si interessant par la diversity de 
ses organes appendiculaires et dont une espece est assez commune 
a Wimereux. Ce Pedalion est une espece marine. II presente, 
outre les deux epaulettes ciliees, six lambeaux d'epithelium 
ciliaire qui forment par leur reunion une couronne presque com- 
plete; les organes appendiculaires de la face orale sont au nombre 
de six : quatre pointes chitineuses et deux boutons a cils raides ; 
les points oculiformes sont au nombre de trois, dont deux 
appartiennent a la face orale." 

On voit que le nom de Pedalion est mentionne deux fois dans 
cet extrait, tandis que celui de Pedalia n'y est pas nomme du 
tout, ni y trouve-t-on une raison quelconque pour ce changement 
de nom, qui se trouve uniquement dans le titre du memoire de 
M. Barrois. 



398 C. F. ROUSSELET ON PEDALION OU PEDALTA. 

La question done s'impose : qui a ecrit ce titre ? est-ce 
M. Barrois, ou le redacteur des Comptes rendus du Congres ? 
J'ignore si le memoire de Barrois a ete publie en entier quelque 
part, et je serai bien content d'en etre informe. La Revue 
Scientifique du temps (No. 13, du 29. Sept. 1877) a publie le 
merne extrait, sans le titre cepenclant, et par consequent le mot 
Pedalia n'y est pas mentionne, mais seulement celui de Pedalion 
a deux fois. 

II y a autre chose encore : par la description que donne Barrois 
il ressort bien clairement que son Botifere n'etait pas Pedalion, 
qui ne vit pas dans la mer, n'a que deux yeux, n'a pas d'epaulettes 
ciliees, ni de couronne ciliee en six lambeaux, ni six organes 
append icul aires sur la face orale. Toute cette description 
s'applique parfaitement a tine espece marine du genre Syncbaeta 
(probablement S. triophthalma Lauterborn, qui porte ses ceufs 
suspendus a la pointe de son pied en nageant), mais pas du tout 
au Pedalion mirum de Hudson, qu'on rencontre un peu partout 
en ete dans des mares d'eau douce. 

II existe deux autres especes de Pedalion (P. fennicum Levander 
et 7-*. oxyure Sernow) qui se trouvent tous deux dans les eaux 
saum aires en Asie, en Egypte, en Amerique et en Australie, 
mais aucune espece n'a encore ete decouverte en mer. 

Par suite de 1'application des regies internationales de nomen- 
clature le nom du genre Pedalion doit tomber, ce nom ayant ete 
applique precedemment a un poisson (Swainson 1832), et a un 
mollusque (Solier 1847). 

II est done utile et necessaire de rechercher qui a le premier 
employe le nom de Pedalia, et j'invite les membres de la Section 
de Zoologie de bien vouloir me communiquer le memoire complet 
de M. Jules Barrois s'il existe, ou toute autre information qui 
pourrait elucider cette question. 

Je ne parle pas de l'Hexarthra de Schmarda, qui pourrait 
tres bien etre une espece encore plus ancienne de Pedalion ; e'est 
une autre question que j'espere pouvoir resoudre sous peu, apres 
m'avoir procure des peches dans le meme marais d'eau saumatre 
a El Kab en Egypte oil Schmarda a decouvert son Hexarthra en 
Mars 1853. 

II resulte de cet expose que M. Jules Barrois (ou peut-etre 
quelqu'autre personne) a non seulement change le nom de 
Pedalion en celui de Pedalia, mais encore l'a applique a un 
Svnchaeta. 



Joarn. Quekett Microscopical Club, Ser. 2, Vol. XII., No. 75, Koccmbc,- 1914. 



399 



THE LIBRARY. 

BOOKS PURCHASED SINCE JANUARY 1914. 

Optical Convention. Vol. II. 1912. 

Sylloge Algarum Omnium. Vol. II. Sect. II. J. Bapt. 

De Toni, 1892. 
Bacteriological Examination of Food and Water. Wm. 

G. Savage, B.Sc, M.D., D.P.H., 1911 

BOOKS AND PHOTOGRAPHS PRESENTED SINCE 

JANUARY 1914. 

Revue Suisse de Zoologie a propos de Rotiferes. Vol. XXII. 
No. 1. January 1914. E. Penard. 

Presented by the Author. 

Sylloge Algarum Omnium. Vol. II. Sect. I. Raphideae. 
J. Bapt. De Toni. 
Presented by the Author. 

My Sayings and Doings. Rev. Win. Quekett. 
Presented by G. W. Watt. 

Cothurindes Muscicoles. E. Penard. 
Presented by the Author. 

Sur quelques Teulaculiferes Muscicoles. E. Penard. 
Un curieux Infusoire, Lbgendrea bellerophon. E. Penard. 

Presented by the A uthor. 

Eighty Photographs of Drawings of Rotifera. By F. R. 
Dixon -Nuttall. 
Presented by F. R. Dixon-Nuttall. 

Eighty Photographs of Rotifera. 
Presented by J. B. Groom. 

Royal Society of Victoria : Further Notes on Australian 
Hydroids. Part II. W. M. Bale, F.R.M.S. 

Presented by the Author. 



400 THE LIBRARY. 

< )donaten-Studien. C. Weseriberg-Lund. 
Presented by the Author. 

WOHNUNGEN UND GEHAUSEBAU DER StJSSWASSERINSEKTEN. C. 

Wesenberg- Lund. 
Presented by the Author. 

FoRTPFLANZUNGSVERHALTNISSE PAARUNG UND ElABLAGE DER 

Susswasserinsekten. C. Wesenberg-Lund. 
Presented by the Author. 

Commonwealth of Australia, Department of Trade and 
Customs : Fisheries. Biological Results of Fishing Ex- 
periments carried on by T.I.S. Endeavour. 1909-14. 

Report on the Hydroida Collected in the Great Australian 
Bight and other Localities. W. M. Bale, F.R.M.S. 

Presented by the Author. 

The Journal of Micrology. Parts I. -IV. 
Presented by H. Edwards. 

For Sale 50 copies reprints of Paper " Lagenae of the 
South- West Pacific Ocean," by Henry Sidebottom. Two Parts. 
Price 2s. Gd. Application should be made to the Librarian. 



401 



THE CLUB CABINET. 

The following Slides have been added to the Cabinet since 
October 1912 : 

Protozoa. 

Presented by G. T. Harris. 
K.A. 106. Actinosphaerium Eichomi (binary fission). 

Infusoria. 

Presented by J. C. Kaufmann. 
K.A. 102. Euglena sp. 

Presented by J. Burton. 
107. Euglena viridis. 

Presented by G. T. Harris. 

103. Ephelota sp. (stained to show nucleus). 

104. Ephelota sp. 

105. Noctiluca miliar is. 

Hydrozoa. 
Presented by G. T. Harris. 

(s = stained.) 

M.A. 4:. Aglaophenia pluma, s. 

50. Aglaophenia pluma (gonophores). 

51. Bougainvillia, muscus. 
14. Cah/cella syringa. 

23. C ampamdaria Jlexuosa, s. 

52 . C ampamdaria flexuosa. 

53. C ampamdaria neglecta. 

54. Clara carnea. 



402 TJ1E CLUB CABINET. 

M.A. 55. Clava carnea, s. 

56. Clava midticornis, s. 

57. Clava squamata, s 
17. Clytia Johnstoni, s. 

58. Clytia Johnstoni. 

91. Clytia Johnstoni (medusa). 
19. Cordylophora lacustris, s. 

59. Cordylophora lacustris (with compound bud), s. 
8. Coryne pus ilia, s. 

60. Coryne vaginata (gonophores), s. 

61. Coryne vaginata [with epiphytal Licmophora /label - 

lata). 

62. Coryne vaginata, s. 

63. Eudendrium insigne, 

64. Eudendrium insigne [with Ephelota : Infusorian). 

65. Gonothyrea Loveni. 

66. Halecium Bcanii. 

67. Hydra fusca. 

68. Hydra viridis (ovary and testes), s. 

69. Hydra vulgaris, s. 

92. Lizzia Blondini (medusa). 

93. Lucernaria fascicularis (medusa). 

70. Obelia dichotoma, s. 

71. Obelia dichotoma. 

72. Obelia geniculata, s. 

73. Obelia geniculata. 

74. Perigonimus sessilis. 

75. Plumularia echinulata. 

76. Plumularia echinulata. 

77. Plumularia echinulata, s. 

78. Plumularia echinulata, s. 

79. Plumularia halecoides, s. 

80. Plamidaria halecoides. 

81. Plumidaria pinnata. 

82. Plumularia setacea. 

83. Plumidaria setacea. 

84. Plumularia setacea (metatophores). 

85. Plumularia siinilis, s. 

86. Plumularia similis. 

87. Podocoryne areolata, s. 



THE CLUB CABINET. 403 

M.A. 28. Sertularia frfiada. 

88. Sertularia pumila, s. 

89. Sertularia pumila. 

90. Serti'liiri'i pwmila. 

Echinodermata. 
Presented by J. Burton. 
N. 19. Plates of Taeniogyrus A llani. 

Rotifera. 
Presented by J. C. Kaufmann. 

Rot. 246. Lacinularia elliptica. 

Turbellaria. 

Presented by H. Whitehead. 

Series 20 : v:ith descriptive notes and diagrams. 

Jficrostomum lineare. 

Phaenocora (Derostomum) punctatum. 

Daly el Ha viridis. 

Daly ell ia diadema. 

Gyratrix herm aphrodit us. 

Dendrocoelum lacteum. 

Planaria alpina. 

Planar ia alpina : tr. and long. sees. 

Planaria gonocephala. 

Polyeelis nigra. 

Poly celis nigra : tr. sec. 

Polyeelis cornuta. 

V B. 35. Tr. sec. (serial) of a Planarian. 

Insecta. 

Presented by T. A. O'Doxohoe. 

R. 402. Scales of Templetonia crystallina. 
403. Scales of Seira Buskii. 

Presented by F. H. jST. C. Kemp. 
399. Xaucoris cimicoides (adult). 



404 THE CLUB CABINET. 

Polyzoa. 

Presented by G. T. Harris. 

M.B. 33. Aetea anguina. 

84. Bowerbankia imbricata. 

85. Pedicellina cernaa. 

80. Pedicellina cemua, var. gracilis. 

Physiological Histology. 

Purchased. (With descriptive, illustrated text.) 

Series 10. The Shin. 

Human scalp, with hair : long, and tr. sees. 

Human scalp, with hair : long, sec, injected. 

Human skin, with perspiration glands : long. sec. 

Human skin, stages of development of perspiration glands : long. 

sec. 
Human skin, with blood vessels injected : long. sec. 
Skin of Dog, with elastic fibres : long. sec. 
Tactile hairs of Ox, with blood sinus : tr. sec. 
Human hair, stages of development : long. sec. 
Human nail : lon^. sec. 



*& 



Series 11. Muscle, bone, etc. 

Human embryo, finger and arm : long. sees. 

Muscle of Ring Snake, with motor nerve plates. 

Muscle of Dog : tr. sec. and long, sec, injected. 

Tendon of Ox : tr. sec. 

Cervical ligament of Ox : sec. 

Bone of Ox : long, sec 

Cranial bone of Dog : sec. 

Joint of Rabbit : median sec. , 

Series 12. Central nervous system. 

Spinal cord and ganglion of Cat : tr. sec. 

Spinal cord of Cat (Golgi preparation : cell impregnation). 

Spinal cord of Dog : tr. sec. 

Cerebral cortex of Cat (Golgi preparation : cell impregnation). 



THE CLUB CABINET. 405 

Cerebellum of Cat (fibre impregnation). 
Cerebrum of Man (fibre impregnation). 
Pineal gland of Ox : tr. sec. 
Pituitary gland of Ox : tr. sec. 
Embryonic spinal cord of Fowl. 
Embryo of Rabbit : tr. sec. 

Series 13. Reproductive organs. 

Penis of Bull : tr. sec. 
Glandula vesicularis of Bull : sec. 
Spermatozoa of Bull. 
Testis of Mouse : tr. sec. 
Umbilical cord of Child : tr. sec. 
Gravid uterus of Pig : tr. sec. 
Oviduct and ovary of Dog : tr. sees. 
Ovary of new-born Kitten : tr. sec. 
Mammary gland of Cow : tr. sec. 

Series 14. Respiratory and urinary organs. 

Lung of Cat : injected. 

Lung of Cat (elastic fibres). 

Lung of Dog (cell pigmentation). 

Trachea of Cat : tr. sec. 

Kidney of Rabbit : injected. 

Kidney of Mouse : tr. sec. 

Bladder of Ox : tr. sec. 

Supra-renal capsule of Ox : tr. sec. 

Embryonic okenian body of Pig : tr. sec. 

Thyroid gland of Man. 

Series 15. Tic Eye. 

Cornea of Ox (gold impregnation). 

Choroid of Ox, showing pigment cells. 

Retina of Ox. 

Optic nerve of Ox : med. sec. 

Eyelid of Calf : med. sec. 

Lachrymal gland of Ox. 

Glands of nictitating membrane of Rabbit. 



406 THE CLUB CABINET. 

Anterior half eye of Ox, without lens : hor. sec. 
Eye of embryo Chick : med. sec. 
Eye of embryo Pig : med. sec. 

Series 16. Organs of hearing, smell and touch. 

Auditory organ of Cat (sensory hairs of ampullae). 

Auditory organ of Cat, membrana tympani : tr. sec. 

Auditory vesicle of embryo Rabbit : long. sec. 

Cochlea of Guinea Pig : med. sec. 

Nasal mucous membrane of Cat : tr. sec. 

Nasal mucous membrane of Rabbit, respiratory portion. 

Olfactory mucous membrane of Rabbit : tr. sec. 

Circum vallate papillae of Ox : mecl. sec. 

Papilla f oliata of Rabbit : tr. sec. 

Pacinian corpuscles in human skin. 

Series 17. Circulatory and blood-forming organs. 

Renal artery and vein of Pig : tr. sec. (fibres stained). 

Renal artery and vein of Pig : tr. sec. (cells stained). 

Human muscle of heart : tr. sec. 

Embryo of Rabbit : tr. sec. in region of heart. 

Human blood : film preparation. 

Human blood : haemin crystals. 

Red bone marrow of Pig. 

Human spleen : sec. 

Human thymus gland (child) : sec. 

Lymphatic gland of Pig : sec. 

Presented by C. L. Curties. 

(Slides remounted by the late Sir Benjamin Ward Richardson 

over 50 years ago.) 

X. 428. Medulla of Cat : tr. sec, injected. 

429. Tongue of Rat : tr. sec, injected. 

430. Duodenum of Turtle : tr. sec. 

431. Intestine of Guinea Pig : vert, sec, injected. 

432. Jejunum of Cat : vert, sec, injected. 

433. Large intestine of Pig : tr. sec, injected. 

434. Retina of Rat : injected. 

435. Toe of Mouse : long, sec, injected. 



THE CLUB CABINET. 407 

X. 436. Human tooth : tr. sec. 

437. Human large intestine : vert, sec, injected. 

438. Human jejunum : vert, sec, injected. 
440. Human sole of foot : vert. sec. 

Freshwater Algae. 
Presented by J. Burton. 

B. 112. Anabaena circinalis. 

122. Apiocystis Brauniana. 

119. Batrachospermum moniliforme. 

114. Bulbochaete sp. 

117. Chaetophora incrassata. 
116. Choaspis stictica. 

(Chrobcoccics turgid us. 
' {0 oelosphaerium Kuetzingianum. 

115. Cladophora flavescens. 

127. Cladophora sp. (Lake Zurich). 
B. 121. Clathrocystis aeruginosa. 

123. Coleochaete scutata. 
125. Cosmarium nitidulum. 

( Cylindrospermum stagnate. 
' {Lyngbya sp. 
125. Jlerismopedia sp. 
41. Micrasterias rotata. 

128. Oscillator ia princeps. 
113. Pandorina morum. 

129. Sphaeroplea annulina. 

118. Spirogyra sp. 

120. Tolypothrix la/iata. 

130. Trichodesmium Ehrenbergi (Atlantic Ocean). 
53. Zygnema sp. 

Presented by Exor. of J. M. Allen. 
B. 111. Ballia pulchrinum. 

Diatomaceae. 

Presented by S. E. Akehurst. 
A. 690. Amphipleura pellucida (realgar). 



408 THE CLUB CABINET. 

Presented by J. Burton. 

A. 688. Rhipodophora meneghiniana, on Ectocarpus. 
689. Achnanthes sp., conjugating on Marine Algae. 

Purchased : mounted in styrax. 

A . 691. A ctin ocyclus pruinosus. 

692. Actinoptychus Bismarckii. 

693. Actinoptychus Grunowii. 

694. Actinoptychus hexagonus. 

695. Actinoptychus maculatus. 

696. Amphora Grevillei. 

697. Asterolampra aemulans. 

698. Auliscus mirabilis. 

699. A uliscus permagna. 

701. Biddulphia Roperiana (showing mode of growth). 

702. Biddulphia Tuomeyi. 

700. Brebissonia Weissjlogii. 

703. Campylodiscus stellatus. 

704. Clyphodesmis Challenger ensis. 

705. Cocconeis extravagans. 

706. Diploneis exemeta. 

707. Kntogonia Daveyani. 

708. Gymatopleura solea. 

709. Hantzschia marina. 

710. Mastogloia cruciata. 

712. Navicula carinifera. 

711. Navicula follis. 

713. Navicula gemmulatula. 

714. Navicula irrorata. 

715. Navicula luxuriosa. 

716. Navicida notabilis. 

717. Nitzschia scalaris. 

718. Omphalopsis australis. 

719. Opephora Schivartzii. 

720. Pinnularia dactylis. 

721. Plagiogramma validum. 
252. Pleurosigma balticum. 

722. Podocyrtis adriaticus. 

723. Raphoneis (uujjhi.ceros. 



THE CLUB CABINET. 40!) 

A. 724. Stephanopyxis Campeachiana. 
725. Stictodiscus Nova- Zealand ic us. 
72G. Stictodiscus par ellel us, var. gibbosa. 

727. Surirella lata, var. robusta. 

728. Surirella Macraeana. 

729. Terpsinoe americana. 

730. Triceratum dejinitum. 

731. Triceratum favus, var. quadrata. 

732. Triceratum favus, var. maxima. 

733. Triceratum fractum. 

734. Triceratum grande. 

735. Triceratum Nova-Zealandicus. 

736. Triceratum Robertsianum. 

Fungi. 

Presented by J. Burton. 

C. 190. Sphoeria herbarum. 
191. Sphoerella rusci. 

Bacteria. 
Presented by J. Burton. 
0. 140. Cohnia roseo-persiciaa. 

Plant Structure. 
Presented by C. J. H. Sidwell. 

E. 38. Leaf of Hydrocharis morsus-ranae\ ri tl n 

q~t * * j ,- -Cellular structure, 

of. Leai oi lradescantia virginica J 

E.A. 55. Leaf of Croton zambesicus 

58. Leaf of Cynoglossum micranthum 

52. Leaf of Onosma alboroseum 
57. Leaf of Onosma stellulatum 

53. Leaf of Onosmodium carolinianum 
24. Leaf of Rhododendron Dalhousia 
56. Leaf of Rhododendron Maddeni 
51. leaf of Trirhodpsma indicum 

54. Leaf of Trichodesma khasiana 



Hairs and 
glands. 



410 THE CLUB CABINET. 

Seeds. 

Presented by C. J. H. Sidwell, 

G. 43. Anagallis arvensis. 

41. Castilleja sp. 

46. Castilleja Cidbertsoni. 

43. Cerastium glomeratum. 

39. Delphinium niacrocentron. 

47. Linaria vulgaris. 

42. Mohavea viscida. 

45. Pedicular is Frederica-Augusti. 

44. Picrorhiza Kurrooa. 

40. Tricholoena rosea. 



ill 



PROCEEDINGS 

OP THE 

QUEKETT MICROSCOPICAL CLUB. 

At the 497th ordinary meeting of the Club, held on March 24th, 
1914, the President, Prof. A. Dendy, D.Sc, F.R.S., in the chair, 
the minutes of the meeting held on February 24th were read and 
confirmed. 

Messrs. C. W. Engelhardt, Harry Albert St. George, E. 
Hermann Anthes, Felix R. W. Brand, Victor M. E. Koch, 
Francis W. Lloyd, Leonard R. Gingell and His Excellency 
Nicholas Yermoloff, K.C.Y.O., were balloted for and duly elected 
members of the Club. 

* 

The list of donations to the Club was read, and the thanks of 
the members voted to the donors. 

The President said : " My attention has been called to the 
fact that Mr. Powell, one of our oldest and best-known members, 
is present this evening. I am also informed that Mr. Powell 
celebrated his eightieth birthday on Saturday last. May I be 
allowed, on behalf of the Club, to offer him our sincere con- 
gratulations on this occasion, and to express our satisfaction that 
he is still able to be present at our meetings ? " 

Mr. J. W. Ogilvy (Messrs. Leitz) exhibited an illuminator for 
opaque objects which consists of a bull's-eye and a stage-condenser 
fitted to a bar which is carried on a stand having universal 
movements. Being in one piece, time is saved in setting up the 
apparatus. 

Mr. N. E. Brown, A.L.S., read " Some Notes on the Structure 
of Diatoms." 

An animated discussion followed the paper, in which the 
President and Messrs. O'Donohoe and Ainslie took part, and to 
which Mr. Brown replied. 

A hearty vote of thanks was given to Mr. Brown for his 
interesting paper. 

The Hon. Sec. read a paper, communicated by Mr. E. M. 
Nelson, F.R.M.S., on " A New Object-glass by Zeiss, and a New 
Method of Illumination." 

Journ Q. M. C, Series II. No. 75. 29 



412 PROCEEDINGS OF THE 

Messrs. Zeiss exhibited the new oil-immersion l/7th on four 
microscopes, and the thanks of the meeting were accorded to 
Messrs. Zeiss and to M. Koch, who represented the firm. 



At the 498th ordinary meeting of the Club, held on April 28th, 
1914, the Vice-President, Mr. D. J. Scourfield, F.Z.S.,F.R.M.S., 
in the chair, the minutes of the meeting held on March 24th 
were read and confirmed. 

Messrs. Edward Carlile, Francis Cooley-Martin, Gerald Burton 
Burton-Brown, M.D., Francis Edward Robotham and Daniel 
Arthur Davies, jun., were balloted for and duly elected members 
of the Club. 

The list of donations to the Club was read and the thanks of 
the members voted to the donors. 

The Hon. Sec. read a note on " A New Low-power Con- 
denser," communicated by Mr. E. M. Nelson, F.B..M.S. 

Mr. C. Lees Curties (Messrs. C. Baker) exhibited both the 
low -power condenser designed by Mr. Nelson and also a simple 
centring-stop holder which he had suggested. 

Replying to a question, Mr. C. Lees Curties said that the 
aperture of the condenser was 0*55. On account of its long 
working distance, the condenser would be particularly useful for 
dark-ground illumination when examining pond-life in a 
trough. 

Mr. M. A. Ainslie said that the Leitz achromatic condenser 
with the top off had an aperture of 0'6, and a working distance of 
one-third of an inch. He would suggest that, when necessary, 
the condenser should be decentred, in order to centre the stop. 
He frequently did this with low powers, when necessary. 

Votes of thanks to Mr. Nelson and to Mr. Curties were pro- 
posed and carried unanimously. 

Mr. N. E. Brown, A.L.S., gave an account illustrated with 
fresh specimens of the flower and a coloured drawing of a longi- 
tudinal section of " The Fertilisation of Vinca minor" He 
said that a very interesting microscopic object was concealed in 
this flower. As regards its fertilisation, a special interest was 
connected with the flower of the periwinkle. The fruit of this 
plant is extremely rare, not only in this country, but also on the 
Continent. The flower has a. very remarkable structure, and a 



QUEKETT MICROSCOPICAL CLUB. 413 

section exhibiting the stigma has several points of interest. At 
the bottom of the tube are two large glands which secrete honey, 
one on each side of the ovary. The ovary has two carpels, which 
are separate, but are united at the top into a single style. This 
goes up, and at the top expands into a wing-like disc, and termi- 
nates with a crown of hairs like a sweep's brush. Some of these 
hairs turn down into five little tufts, forming little alcoves, which 
play very important functions. From the corolla arise five 
stamens. The anthers are raised above, and are so curved over as 
to enclose the whole and prevent ingress except between each pair 
of stamens. The anthers open while in the bud, and then shed 
their pollen, which, when the flower opens, is seen to be deposited 
in five little heaps. Underneath the wheel-like formation, often 
spoken of as a stigma, we find a frill-like, orange-coloured body, 
which is not of the same depth all round, but opposite the little 
alcoves already referred to deepens slightly. The true stigma is 
formed by this curtain, or frill, and there we find the true stig- 
matic tissue. Now as regards fertilisation. Insects (bees) come 
for the nectar situated at the base. Grooves guide the tongue 
between two anthers and past the upper ledge of the shelf, or 
frill. Here it passes the little masses of pollen, which are slightly 
glutinous, and, before reaching the honey-glands, comes in contact 
with a wet, viscid fluid. ^Yhell the tongue is withdrawn, the 
smeared surface comes in contact with the mass of pollen, which 
adheres to it. But the plant does not want to part with all its 
masses of pollen, and so some is scraped off the proboscis by the 
projecting hairs, and remains until the visit of another bee, 
which, perhaps, has already visited a periwinkle flower. The 
tongue passes down past the stigmatic frill ; but in coming back 
scrapes the pollen off on the under side, no trace of pollen 
remaining on the part of the tongue previously smeared with 
the viscid matter. This is the manner in which the plant is 
fertilised. Last year the speaker had examined many plants in 
order to see if they had been fertilised. It is commonly stated 
that V. minor is infertile to its own pollen, and so seeds are rare. 
Nearly all plants in one locality are probably products of one 
plant, and have not come from seed. Of the plants examined, 
70 per cent, had been fertilised by insects ; but no fruit of any 
kind developed on the clump under observation. Mr. Brown this 
year had fertilised one hundred flowers ; but it is yet too early to 



414 PROCEEDINGS OF THE 

be able to report any results. This year was noticeable for a 
great dearth of pollen, all the anthers being more or less barren. 
He awaited with interest the result of his artificial pollination. 

The Chairman said that at first thought it might possibly be a 
case of over -elaboration. 

Mr. R. Paulson asked if Mr. Brown had cut sections to see if 
any of the pollen grains had thrown out tubes. He preferred to 
distinguish between the terms " pollination " and " fertilisation." 
As is well known, there are some plants in the British flora 
where pollination does take place, but which are infertile. As 
an instance he would mention the lesser celandine Ranunculus 
fizaria. Had Mr. Brown ever seen any seeds of this plant 1 It 
might be imagined that its seeds would be very numerous ; but 
this is not the case. It does seem that in many plants we have 
instances of over-elaboration. He would instance orchids and 
violets and especially with regard to violets. Violets produce 
abundant seed, not by the attractive flowers, but by little green 
flowers which are usually missed by the ordinary observer. 
These little green flowers never open and the anthers shed their 
pollen directly on to the stigmas. 

Mr. 0. E. Heath asked whether the pollen of Vinca minor had 
been seen to form tubes. 

The Hon. Secretary suggested that the pollen might be tested 
practically, under the microscope, in a weak solution of sugar- 
and-water. If the grains did put out tubes, he thought it would 
prove the possibility of fertilisation. 

Mr. Brown, replying, said that even if the pollen grains pro- 
duced tubes in a sugar-and-water solution, it would be no 
guarantee that they would also do so in the flower. He intended, 
however, to examine the pollen and also to cut sections. 
Regarding the celandine, in the South of England it seeds quite 
freely. It is possibly a question of temperature. Not all violas 
have cleistogamous flowers ; some usually produce seed from the 
ordinary open flowers. 

The Hon. Secretary (Mr. James Burton) read a note on "An 
Abnormal Form of Arachnoidiscas ornatus." He wished to draw 
attention to the plate of Arachnoidiscus, by Beck, in Carpenter's 
The Microscope and its Revelations, a copy of which was on the 
table. The drawing represented the diatoms entire and still 
attached to the seaweed on which they occurred. It showed their 



QUEKETT MICROSCOPICAL CLUB. 415 

living form. That which we are accustomed to find on mounted 
slides is only a part of the organism. He was exhibiting, under a 
microscope, a slide given him by Mr. Williams, of Folkestone, 
which displayed very beautifully the box-like form of this diatom. 
It consists of a top and a bottom circular plate, known as valves, 
to each of which is attached a ring, called by some authors the 
girdle ; that of the top or lid, as it might be called fitting 
outside that of the lower, or box -like, part. The whole closely 
resembles an ordinary circular " chip ' ! specimen-box. On the 
slide exhibited, examples of an abnormal form occur, in which 
the bottom of the box has the "girdle" greatly elongated, the 
"lid" still remaining shallow, as in a normal form. This struc- 
ture gives the diatom, when viewed sideways, the appearance of a 
cylinder, instead of that of a disc with but slight depth, and when 
observed under a binocular with dark-ground illumination the 
difference is very striking. The girdle is marked by circles of 
lines running round, as though it were composed of superimposed 
rings. On the rings are small projections or points. The 
frustules are empty, and there is no appearance of the com- 
mencement of dividing-walls inside, which might have indicated 
that the unusual form was owing to the beginning of the process 
of subdivision. In a normal form the depth was 30 /x ; in a case 
where subdivision was far advanced the depth was 54 /x. In an 
abnormal specimen the depth was 96 /x; another was 105 /x. The 
diameter in all the forms measured is fairly constant, varying 
from 105 /x to 114 /x. The abnormal form is only known to occur 
in one collection of material from Mauritius, and in that the 
percentage is very small. No explanation or suggested cause of 
the unusual form was forthcoming. 

Mr. Burton was complimented on the opportunity of bringing 
this interesting slide under the notice of members. 

Several members had interesting exhibits under microscopes, 
Mr. G. K. Dunstall showing Flosadaria cyclops, which is worthy 
of being recorded. 



At the 499th ordinary meeting of the Club, held on May 26th, 
1914, the President, Prof. A. Dendy, D.Sc, F.R.S., in the chair, 
the minutes of the meeting held on April 28th were read and 
confirmed. 

Messrs. Henry Turing Peter, Sydney G. Bills and .Robert 



416 PROCEEDINGS OF THE 

William Buttemer were balloted for and duly elected members of 
the Club. 

The list of donations to the Club was read and the thanks of 
the members voted to the donors. 

Mr. W. R. Traviss exhibited a number of specimens of insects 
in amber. 

Mr. A. E. Hilton read " Some Notes on the Cultivation of 
Plasmodia of Badhamia utricularis" He said that a free- 
flowing mass of naked and almost undifferentiated protoplasm, 
such as we have in a plasmodium of B. utricularis, suggests 
opportunities for biological experiments with unusual promise of 
success. 

The chief purpose of this paper, Mr. Hilton said, was to place 
on record the results of experiments made during the last few 
months, which suggest a method of continuous cultivation of 
plasmodia of B. utricularis at once simple and practicable. 

The President said they were very much obliged to Mr. Hilton 
for his very interesting and practical paper, which he should find 
of great value to himself, as he had hitherto had great difficulty 
in feeding this organism. He hoped the methods described would 
come into general use for laboratory work, where the plasmodium 
was very useful as an illustration. He should like to ask 
Mr. Hilton if he had tried how long he could keep the plas- 
modium in a dry state on the blotting-paper. Mr. J. J. Lister 
at Cambridge used to feed it on fungus, but this was sometimes 
difficult to get. He hoped that many members of the Club would 
experiment in the manner suggested. 

Replying to several questions, Mr. Hilton said the dried 
sclerotium is capable of reviving after at least three years; but 
it must be kept dry, and never allowed to become damp. After 
so long a period, it might take four or five days to recover. He 
could not say if it were possible to cultivate the plasmodium form 
from sporangia. A difference in colour has been noticed in 
specimens cultivated on plain bread compared with specimens 
fed on the special mixture. The former are a lighter yellow 
than the latter ; but various shades of yellow are present even in 
one plasmodium. He had found a constant temperature of about 
50 F. the best. 

A very hearty vote of thanks was accorded to Mr. Hilton for 
his paper. 



QUEKETT MICROSCOPICAL CLUB. 417 

The Hon. Secretary read a paper on " Binocular Microscopes," 
communicated by Mr. E. M. Nelson, F.R.M.S. In recent years 
several binoculars have been introduced, none of which, however, 
can be called new. The first, the Greenough, by Zeiss (Journal 
R.M.S., 1897, pp. 599, 600), was a twin microscope a form of 
binocular invented by Pere Cherubin d'Orleans nearly three 
hundred years ago. The second by F. E. Ives, in 1902 {Journal 
R.M.S., 1903, p. 85) is very similar to one designed by Wenham 
in 1866 as a counterblast to Powell's high-power binocular, in 
which the whole beam is sent into each eye. The third, a modifi- 
cation of the second, by Leitz {Journal R.M.S., 1914, p. 5), and 
the fourth, by Beck, which is very similar to that of Ives. 

Mr. Nelson concluded his paper by some remarks on the 
position of the two new binoculars. From what has been said, 
it will be seen that they are a class by themselves. It would be 
quite inaccurate to entertain the idea that these instruments are 
a new kind of stereoscopic binocular constructed to enter into 
competition with, and finally to supersede, existing binoculars of 
the Wenham and Stephenson type, for they only possess the first 
attribute stereoscopism in a limited manner. Their use is 
confined to the employment of full Ramsden discs in each eye 
that is, for work with non-stereoscopic images. When prolonged 
work is undertaken with one of the new binoculars, great relief 
and comfort to the eyes will be secured. 

Messrs. Beck, represented by Mr. C. Beck and Mr. Creese, 
exhibited two of their new model high-power binoculars, one 
giving an excellent image of Pleurosigma angulation with a 1/1 2th 
oil-immersion, and on the other stand a lower power exhibited to 
perfection, first, stereoscopic, and, second, pseudo-stereoscopic 
vision obtained by altering the tube-length. Mr. Creese also 
exhibited a Wenham binocular with a l/6th objective, giving a 
perfectly evenly illuminated field at 300 diameters of a section of 
the eye of the drone-fly. 

Messrs. Leitz's London representative, Mr. J. W. Ogilvy, 
showed seven stands of their new model, with powers ranging 
from 1/1 2th oil-immersion apochromat and 1,500 diameters to 
1 in. and x 35. Two Leitz-Greenough models with low powers 
were also exhibited. The preparations shown included Amphi- 
pleura pellucida, Poclura scale, rock sections, and histological 
preparations. 



418 PROCEEDINGS OF THE 

Mr. Nelson also sent for exhibition a photograph of a new 
slide, designed by Mr. G. Nelson, for the portable Greenough, to 
hold three pairs of objectives. It allows the powers to be changed 
by moving the slide forward, and, in brief, is for the Greenough 
what a rotating nosepiece is for an ordinary microscope. 



At the 500th ordinary meeting of the Club, held on June 23rd, 
1914, the Vice-President, Mr. E. J. Spitta, L.R.C.P., M.R.C.S., 
in the chair, the minutes of the meeting held on May 26th were 
read and confirmed. 

Messrs. Geoffrey Norman, Charles James Reeves King, William 
Henry Scott, Charles Worthington Hawksley, Martin Herbert 
Oldershaw and Edmund John Weston were balloted for and duly 
elected members of the Club. 

The list of donations to the Club was read and the thanks of 
the members voted to the donors. 

Mr. Watson Baker, jun., read a short paper describing a 
series of sections of fossils from the Coal Measures. Many of 
these were not only rare, but were almost unique in the beautiful 
manner in which they showed the various structures, both of 
plants and animals. They were exhibited under a number of 
microscopes, lent and arranged for the occasion by Messrs. 
Watson & Son. There were on view, also, whole specimens 
still attached to the rock in which they were found. Mr. Watson 
Baker said the specimens had been sent to him by a well-known 
authority on palaeo-botany, and as many of them were of unusual 
merit, he thought the Club would like to see them. He then 
gave an interesting description in some detail : a condensed account 
is as follows : No. 1. A specimen of the lower jaw of Elonicthys, 
with teeth in situ. No. 2. Flank scales from the same. Elonic- 
thys is a genus of fishes having a bony armour or a skeleton. 
Devonian and Carboniferous, they existed in large numbers and 
great variety, some attaining a great size. No. 3. A specimen of 
the Caeleanthidae (hollow-spined fishes), which range from the 
Upper Devonian to the Chalk. Specimens of these in situ were 
on the table. Nos. 4 and 5 were sections of teeth of species of 
shark, Diplodus equilateralis and D. gibbosus ; also an uncut 
example of one of the teeth. Nos. 6 and 7. Sections of coal from 
Mossfield Colliery, Longton, showing various vegetable tissues. 



QUEKETT MICROSCOPICAL CLUB. 419 

Microspores and Megaspores reproductive organs resembling 
those of modern Lycopods were clearly evident. No. 8. Plant 
remains of a similar character. No. 9. A number of Fern 
sporangia, showing the annulus, etc., embedded in a matrix of 
fragmentary plant remains. No. 10. A section showing the 
seeds of Cordaites : a genus of fossil-plants allied to some of the 
recent Gymnosperms. 

The chairman remarked on the very beautiful series of micro- 
scopical slides, and on the hand specimens on the table, and pro- 
posed a vote of thanks to Mr. Watson Baker, which was responded 
to heartily. 

The Hon. Secretary read a letter from Dr. M. C. Cooke, and 
extracts from others received from Alphaeus Smith, Albert D. 
Michael and G. 0. Karrop, who were unable to be present, con- 
gratulating the Club on its continued prosperity, and wishing 
it all success in the future. These were received with much 
appreciation by the meeting. 

The chairman then gave a short resume of the history of the 
Club. He said that though named in honour of the celebrated 
Dr. Quekett, it was not founded by him, originating four or five 
years after his death. It was considered by a Mr. Gibson that 
an association of amateur microscopists was desirable, and he put 
an announcement into Hardwicke's Science Gossip to that effect. 
The idea at first seemed to be to combine music and microscopy 
at the evening meetings. The suggestion was rapidly and 
enthusiastically taken up, and in July 1865 the Club was 
definitelv started. Soon the meetings came to be held at 
University College ; but it is curious to note that some of the 
preliminary ones were held in Hanover Square, so that, again 
occupying rooms in Hanover Square, the Club has returned to 
its old locality. Among the very earliest members Mr. Lewis's 
name appears. He was elected in April 1866 forty-eight years 
ago, and has held the position of honorary reporter from the 
very early years of the Club. He has attended 485 out of 
the 500 ordinary meetings almost certainly a record and 
several of the omissions occurred only this last winter, owing 
to illness and advancing years. Another very old member is 
Mr. Alphaeus Smith, who held the post of hon. librarian 
for forty years, and is still a member, though not on the active 
list. Dr. M. C. Cooke, Mr. J. Terry, Mr. T. H. Powell, and 



420 PROCEEDINGS OF THE 

Mr. Millett all joined in 1865, and are still members. Dr. 
Spitta referred to the work of Dr. Karop and Mr. Earland, 
both of whom had been hon. secretaries in former years, and to 
whom the Club was greatly indebted for its success. Lantern 
photographs of Dr. Quekett and of pages of the old attendance- 
books, showing names of original members, and various scenes 
connected with the Club's life, were thrown on the screen. 
Dr. Spitta wound up his interesting and delightfully humorous 
discourse by recounting a supposed reverie (in verse) in which he 
saw most of the present officers and prominent members coming 
into a meeting, and detailed with delicate skill and good nature 
their hobbies and characteristics. He then called upon some of 
the older membersof whom a satisfactory number had been 
able to attend to say a few words. 

Mr. Lewis made a little speech, in which he disclaimed the 
title of "veteran," as he said Mr. Powell was before him, and he 
spoke of Mr. A. Smith, who joined just after him. He was able 
in some respects to supplement the chairman's remarks of what 
took place at the earliest meetings, and said in conclusion that 
" though my recent illness has shaken my health, and I shall 
have to give up many things, the last I shall give up will be the 
Quekett Microscopical Club, from which I have derived much 
information, and have made many old and valued friends, and no 
one connected with the Club has its interests more at heart than 
myself." His remarks were received with enthusiasm by the 
members, who showed their appreciation by prolonged cheers. 

Mr. T. H. Powell (forty-nine years a member) wound up what he 
said by remarking that he always enjoyed himself at the pleasant 
meetings of the Quekett. Mr. F. Enock addressed the meeting 
appropriately, and was followed by Mr. Earland, who made an 
interesting and humorous speech on some of his experiences as 
secretary. He, like others, referred to Mr. Lewis, and rejoiced 
to see him still at the seat at the reporter's table he had occupied 
so long. Again the audience showed their appreciation by cheers. 
Mr. Hilton followed. He pointed out that till quite recent 
years, during the long career of the Club, there had been only 
two librarians, owing to Mr. Smith's long tenure of the office. 
He also remarked on the large attendance at the meetings now, 
saying that they could not realise what it was to have a meeting 
with only six or even fewer present ; but stated that there was 



QUEKETT MICROSCOPICAL CLUB. 421 

no less good will and friendliness among them now, and desire 
to help and welcome new-comers. He felt it had been a great 
advantage to himself to belong to the Club. 

The chairman then proposed a rhyming " toast," wishing 
" Long life to the Club," and, at his request, the members rose in 
a body and " made the welkin ring " in their concurrence with 
the sentiment he had so deftly expressed. 

To wind up a very pleasant evening, Dr. S pitta exhibited 
upon the screen a series of lantern views of natural objects, 
beautifully nature-coloured. Many of various flowers were 
wonderful productions, with the colours unbelievably soft and 
lifelike, and some of the insects were not less successful. The 
meeting then broke up, many staying, however, to examine more 
leisurely Mr. Watson Baker's unique specimens. 

Unfortunately too late to be read at the meeting, a Marconi- 
gram arrived from the late hon. secretary, Mr. W. B. Stokes, at 
Montreal : " Congratulations five hundredth meeting." (Signed) 
Stokes. 



422 



OBITUARY NOTICE. 

MORDECAI CUBITT COOKE, M.A., LL.D., A.L.S. 

(Born July 12th, 1825; died November 12th, 1914.) 

It is with feelings of great regret we have to record the death, in 
his ninetieth year, of Dr. M. C. Cooke, the " Father of the Club," 
which took place on November 12th at his residence in Southsea. 

Dr. Cooke was born in 1825 at the village of Horning in 
Norfolk, where his parents kept a general shop. From an early- 
age he was dependent upon his own resources, und was in turn 
employed as draper's assistant, teacher in a National school and 
lawyer's clerk. As an assistant in the Indian Museum he at 
last found congenial occupation, and when that institution was 
abolished spent some time at the South Kensington Museum, in 
the Mycological Department. He afterwards joined the Her- 
barium at the Royal Botanic Gardens, Kew, and was for twelve 
years (1880-92) in charge of the Cryptogamic Department ; in 
the latter year he retired on a pension. 

During this time he incorporated his own herbarium, con- 
taining 46,000 specimens, with the existing collection at Kew, 
as well as the collection of fungi presented to Kew by the 
Rev. M. J. Berkeley. His figures of fungi, mostly coloured and 
numbering 25,000 plates, are also at Kew. 

His first important work was the Handbook of British Fungi, 
in two volumes, published in 1871, followed by Mycogra'phia, or, 
coloured figures of fungi from all parts of the world, 113 plates ; 
Handbook of Australian Fungi ; and Illustrations of British 
Fungi, 1,200 coloured plates. In addition to the above, over 
300 articles on mycological subjects are credited to Dr. Cooke by 
Lindau and Sydow ; for a period of fifteen years he also edited 
Grevillea, a journal devoted to cryptogamic botany. 

After his retirement in 1892 Dr. Cooke retained his interest in 
fungi, and until 1904 attended the annual fungus foray of the 
Essex Field Club. Recently his eyesight failed, though his mind 
remained keen and active. He was honorary M.A. of Yale, and 



OBITUARY NOTICE. 423 

LL.D., and in 1903 he had the honour of being awarded the 
gold medal of the Linnean Society. 

In addition to his scientific publications, he was the author 
and editor of a number of popular books in Natural History, and 
was at the time associated with the publisher of Hardwicke's 
Science Gossip, of which journal he was editor from its beginning 
in 1865 until December 1871. 

In the Journal of the Q.M.C. for November 1899 will be found 
" Early Memories of the Q.M.C," a short paper contributed by 
Dr. Cooke on the early history of the Club. Dr. Cooke was one 
of the eleven members who attended the preliminary meeting 
held on June 14th, 1865, and the meeting on July 7th, when 
the Q.M.C. originated, and he was then elected one of its 
first Vice-Presidents. He was President in 1882 and 1883, 
and was elected an honorary member in 1893. He was always 
a very active spirit at committees, meetings and excursions as 
long as he attended ; his last recorded attendance was in May 
1900. 

Many of us will recall that our first excursions into the fairy- 
land of science were made under the guiding hand of Dr. M. C. 
Cooke. 



424 



Table for the Conversion of English and Metrical 
Linear Measures; Yard and Metre at same Temperature. 



1 -i- 

2 


mm. 


1 + 


A 4 


1 -r- 


f l 


1 + 


A 


H 


A* 


12-70 


27 


940 


53 


479 


79 


321 


125 


203 


*> 

o 


8-4 6 


28 


907 


54 


470 


80 


317 


130 


195 


4 


6-35 


29 


876 


55 


462 


81 


313 


135 


188 


5 


5-08 


30 


846 


56 


453 


82 


310 


140 


181 


6 


4-23 


31 


819 


57 


445 


83 


306 


i 145 


175 


7 


3-63 


32 


794 


58 


438 


84 


802 


150 


169 


8 


3-17 


33 


76!) 


59 


430 


85 


299 


155 


164 


9 


2-82 


34 


747 


60 


423 


86 


295 


160 


159 


10 


2-54 




725 


61 


416 


87 


292 


165 


1 54 


11 


2-31 


3(5 


705 


62 


410 


88 


289 


170 


149 


12 


212 


37 


686 


63 


403 


S!) 


285 


175 


145 


13 


1-95 


38 


668 


64 


397 


90 


282' 


180 


141 


14 


1-81 


31) 


651 


65 


391 


91 


279 


185 


137 


15 


1-69 


40 


635 


66 


385 


92 


276 


190 


1 34 


16 


1-59 


41 


619 


67 


379 


93 


273 


195 


130 


17 


1-49 


42 


605 


68 


373 


94 


270 


200 


127 


18 


1-41 


43 


591 


69 


368 


95 


267 


205 


124 


19 


1-34 


44 


577 


70 


363 


96 


265 


210 


121 


20 


1-27 


45 


564 


71 


358 


97 


262 


215 


118 


21 


1-21 


-if ; 


552 


72 


353 


98 


259 


220 


115 


22 


115 


47 


540 


73 


348 


99 


256 


225 


113 


23 


1-10 


48 


529 


74 


343 


100 


254 


230 


110 


24 


1-06 


49 


518 


75 


339 


105 


242 


; 235 


108 


25 


1-02 


50 


508 


76 


334 


110 


231 


i 240 


106 




A 4 


51 


498 


77 


330 


i 115 


221 


i 245 


104 


26 


977 


52 


488 


78 


326 


120 


212 


! 250 


102 



As the measurements of many microscopical objects are given in 
fractions of an inch in English literature, and in metrical measure in 
foreign works, the above table has been drawn up to facilitate com- 
parison. Its use is obvious. Examples : l/7th inch = 3 63 mm., l/58th inch 
= 438 ft, or -438 mm. For fractions smaller than 1 /250th inch that portion 
of the table between the figures 26 and 99 may be used by cutting off 
the last figure for hundredths, and the two last figures for thousandths. 
Examples: 1 /270th inch = 94*0 p, or -0940 mm.; l/7900th inch = 321 p, 
or "00321 mm. When that portion of the table between the figures 100 
and 250 is used it is only necessary to cut off the last figure for thousandths 
and the two last figures for ten thousandths. Examples : l/1350th inch 
= 18-8 p, or -0188 mm., l/16500th inch = 1-54 p, or -00154 ram. The 
conversion of millimetres into fractions of an inch is performed in the same 
manner; thus, 529 p or -529 mm. = l/48th inch; 39-7 p or -0397 mm. 
= l/640th inch ; 2-62 p or -00262 mm. = l/9700th inch ; 1-04 p or -00104 
mm. = l/21500th inch; -977 p or -000977 mm. = l/26000th inch, and 
so on. E. M. N. 



425 



THE EARLY HISTORY OF THE QUEKETT MICRO- 
SCOPICAL CLUB. 

By R. T. Lewis, F.RM.S. 

The Quekett Microscopical Club this year attains its Jubilee, 
and, as no doubt many of its present members are unacquainted 
with its early history, it has been thought that some account of 
this would be of interest. 

Hardwicke's Science Gossip was started in January 1865, and 
in the May number of that periodical a letter appeared from 
Mr. W. Gibson, suggesting that a Society for Amateur Micro- 
scopists on similar lines to those of the Society of Amateur 
Botanists (of which he was a member) would be desirable, as 
being a means of bringing together those having similar tastes, 
who could meet to discuss difficulties and assist one another in a 
manner not provided for by the existing Society. Monthly meet- 
ings and a small subscription were proposed, and persons interested 
in the matter were invited to co-operate. The Editor of Science 
Gossip gladly inserted this communication, and, being himself the 
President of the Society of Amateur Botanists at the time,, 
entered fully into the project, and together with Mr. W. M 
Bywater and Thomas Ketteringham met at the house of the 
former in Hanover Square, and having discussed its feasibility, 
decided that such a society should be established, and should be 
named " The Quekett Club " after the name of the distinguished 
Professor of Histology * who had died :a short time previously, 

* John Thomas Quekett, b. 1815. In 1856 he succeeded Prof. Owen as 
Conservator of the Hunterian Museum, and was appointed Professor of 
Histology, which post he held until his death. He was elected F.R.S. in 
1860, and died in 1861. He was Secretary of the Microscopical Society of 
London for nineteen years. His Practical Treatise on the Use of the Micro- 
scope is, or was, well known. 

Journ. Q. M. C, Series II. No 76. 30 



426 R. T. LEWIS ON THE EARLY HISTORY OF THE 

A meeting of twelve gentlemen known to be interested in the 
microscope was therefore called, and took place on June 14th, 
1865, at the offices of Mr. Robert Hardwicke in Piccadilly. This 
meeting was attended by eleven out of the twelve summoned, the 
chair was taken by Mr; M. C. Cooke, and on the motion of Mr. 
W. Gibson it was unanimously resolved that such a Club should 
be formed, and on the motion of Mr. E. Jaques it was also 
unanimously decided that a provisional Committee of five gentle- 
men, with Mr. Bywater as Secretary, should be appointed, and 
charged with the duty of deciding as to the best means of carrying 
out the object in view, and to report the result of their delibera- 
tions to an adjourned meeting to be held on July 7th. This 
meeting, which was held at St. Martin's National Schools, was 
attended by about sixty gentlemen, when four suggestions made 
by the Committee were discussed and severally put to the meeting, 
it being eventually decided : 

(1) That the new society should be called the Quekett 
Microscopical Club. 

(2) That the meetings be held on the fourth Friday of every 
month. 

(3) That the subscription be 10s. per annum, payable in 
advance, and be considered due as from July 1st, 1865. 

(4) That the business of the Club be conducted by a President, 
two Vice-Presidents, twelve Members of Committee, a Secretary 
and a Treasurer. 

It was further decided that the provisional Committee should 
be empowered to carry on the business of the Club and to receive 
subscriptions until the appointment of regular officers had been 
duly made ; the meeting was then adjourned until August 4th, 
1865. At the adjourned meeting, which was also held at 
St. Martin's Schools, a series of eleven By-laws were passed, 
Dr. Edwin Lankester was elected the first President of the Club, 
with Messrs. M. C. Cooke and P. le Neve Foster as Vice-Presi- 
dents, Mr. Robert Hardwicke as Treasurer, Mr. W. M. Bywater 



QUEKETT MICROSCOPICAL CLUB. 427 

Secretary, and twelve members to serve on the Committee. 

The first Ordinary Meeting was held on August 25th, 1865, in 

the rooms at 32, Sackville Street, when the President took 

the chair and gave an interesting inaugural address, and the 

Quekett Microscopical Club was thus fairly started on what has 

proved to be a successful career. The rapid increase in the 

number of members soon made it apparent that the room in 

Sackville Street was not large enough for the purpose, and the 

Eighth Ordinary Meeting was held in the Library of University 

College, kindly placed at the disposal of the Club by the Council 

of the College, through whose courtesy the meetings continued to 

be held there until 1889. Dr. Lankester was succeeded in the 

Presidency by Mr. Ernest Hart, and it was in October 1866 

that the suggestion was made that the proceedings of the 

Club were now of sufficient importance to deserve some record, 

and in the following month reports were taken by Mr. R. T. 

Lewis, who has carried out this duty to the present time. The 

earlier papers read at the meetings were in some instances 

published in the Microscopical Journal or in Science Gossip, but 

they were subsequently printed in the Journal of the Club, 

which was commenced in 1868 under the editorship of Mr. W. 

Hislop. 

The first Soiree of the Club was held at University College 
on January 4th, 1867, and notwithstanding a heavy fall of 
snow and frost of exceptional severity, in consequence of 
which vehicles were only to be obtained at a high premium, 
it was attended by a large number of members and their 
friends, and was deemed to have been a decided success. 
Profiting, however, by the experience gained on this occasion, 
future Soirees were held somewhat later in the year. The 
number of members at the end of the second year of the 
Club's existence was 273. Eleven Field Excursions took place, 
the Cabinet contained 260 slides, and an "Exchange of Slides 
Committee" was appointed. 



428 R. T. LEWIS ON THE EARLY HISTORY OF THE 

Mr. Arthur E. Durham was the third President, and held the 
office for two years, during which period the Journal of the Club 
made its first appearance, the extra meetings on the second 
Friday in each month were commenced, and the first dinner took 
place at Leatherhead, Mr. Suffolk's classes* were restarted, and 
the number of members was reported as having reached 512. It 
was towards the beginning of 1868 that a member of the Com- 
mittee began to agitate for the admission of women as members, 
a proposal strongly deprecated by his colleagues as being sub- 
versive of the interests of the Club. This gave rise to considerable 
opposition from the members generally, and much merriment 
was created by the circulation of sketches by Mr. Suffolk and 
Mr. Lewis, and by the issue of a skit purporting to be the 
report of a meeting held two years ahead and embodying most 
of the objections to the scheme. It was, however, formally- 
proposed at the Ordinary Meeting in March 1868, Dr. Tilbury 
Fox in the chair, but on the resolution being put it found only 
two supporters, and was therefore negatived by an overwhelming 
majority. 

At the Annual Meeting in 1869 Mr. P. le Neve Foster suc- 
ceeded Mr. Durham as President, but the latter took the chair 
at the November meeting, when a handsome testimonial was 
presented to Mr. Bywater on his retirement from the position 
of Secretary, the duties of that office having been taken over 
by Mr. T. C. White. In 1870 the members had increased so 
much that it became necessary to reduce the number of invitation 
tickets issued for the Annual Soiree, a charge being made for 

* Mr. W. T. Suffolk conducted a class for beginners during the winter 
of 1865-6 in a room at the Society of Arts, kindly placed at his disposal 
for the purpose by Mr. P. le Neve Foster. At this he gave useful and 
practical information on the management of the microscope, the mounting 
of objects, etc. The class was suspended during the summer months, but 
was resumed during the winter of 1866-7, and was fairly well attended 
but as there is no later mention of it, I infer that it was not again started,, 
but occasional demonstrations at the Gossip Meetings seem to have 
taken its place. 



QUEKETT MICROSCOPICAL CLUB. 429 

those wanted in excess, the sale of which realised =5 7s. Qd., 
a,nd this was given as a donation to University College Hospital. 
The next four Presidents, Dr. Lionel S. Beale, Dr. Robert 
Braithwaite, Dr. John Matthews and Mr. Henry Lee, each held 
the office for two years. At the Annual Meeting in 1873 
Mr. White retired and was succeeded by Mr. J. E. Ingpen, with 
Mr. E. Marks as Assistant Secretary. Mr. Robert Hardwicke, 
the first Treasurer of the Club, died in 1875, and was succeeded 
in the office by Mr. F. W. Gay. In 1878 Prof. T. H. Huxley 
was elected President, being followed by Dr. Spencer Cobbold in 
1879, Mr. T. C. White in 1880 and 1881, Dr. M. C. Cooke in 
1882 and 1883, Dr. W. B. Carpenter in 1884, Mr. A. D. Michael 
in 1885, 1886 and 1887, and Mr. B. T. Lowne in 1888-9. The 
<3ate of the Annual Meeting was altered to the last Friday in 
February in 1888. 

The last meeting in the Library of University College was 
held on February 22nd, 1889, but the Council of the College 
generously placed their Mathematical Theatre at the disposal 
of the Club. This room, however, was found unsuited to their 
purpose, and arrangements were made for removal to 20, Hanover 
Square. This necessitated a change of the meeting nights to 
first and third Fridays, and no Ordinary Meetings were after- 
wards held in July and August. The history of the Club during 
the last twenty-four years need not be recorded here, as all 
particulars are to be found in the reports, and are doubtless 
well known to the majority of the members. Briefly, however, 
since its commencement in 1855, it has had twenty-three Presi- 
dents, seven Secretaries, and has published sixteen volumes of its 
Journal. 

Of the original members but few are now left, and of those 
who joined in the first year only two now are seen at the 
meetings. Mr. W. Gibson, whose suggestion led to the Club's 
formation, does not appear to have contributed to the pro- 
ceedings, though he continued to be a member for eighteen 



430 R. T. LEWIS, EARLY HISTORY OF QUEKETT MICROSCOPICAL CLUB, 

years. Mr. M. C. Cooke, who took the chair at the preliminary 
meetings, was elected an honorary member in 1893, and con- 
tinued to take a lively interest in the well-being of the Club up 
to the time of his death, which occurred in his ninetieth year, 
only a few months ago. 



Journ. Qutkett Microscopical Club, Str. 2, Vol. XJL, No. 7(5, April 1915. 



431 



A NEW COPEPOD FOUND IN WATER FROM HOLLOWS 

ON TREE TRUNKS. 

By D. J. Scourfield, F.Z.S., F.R.M.S. 
{Read November 24th, 1914.) 

Plates 24 and 25. 

The search for plants and animals in unusual and unlikely 
places is always interesting, and may be sometimes richly re- 
warded. As a case in point, and the one which led directly to the 
discovery of the new species of Copepod that I wish to describe 
in this paper, we may consider what has been done in the 
elucidation of the fauna living in the little natural cups formed 
by the bases of the leaves of plants belonging to the Order 
Bromeliaceae, i.e. the order to which the pine-apple belongs. 

It was in 1879 that the celebrated naturalist Fritz Miiller, 
who was at that time associated with the National Museum in 
Rio de Janeiro, called attention to the fact that the water con- 
tained in the little cups just referred to was tenanted by various 
forms of animal life. In particular he described a new Ostracod, 
representing a new genus, Elpidium bromeliarum, which occurred 
almost constantly in association with the Bromeliaceous plants 
in the forests of Brazil, and strangely enough was to be found 
in no other situation (5, 6, and 7). 

Since that date a number of other investigators have from 
time to time examined these little collections of water retained 
by the leaves of Bromeliaceous plants, and I may here mention 
that soon after I became acquainted with the work of Fritz 
Miiller I commenced to look for Entomostraca in these situa- 
tions at the Royal Botanic Gardens, Regent's Park, and at Kew. 
My curiosity was gratified by finding the remarkable blind 
Copepod, Belisarius viguieri, which had not previously been 
found in this country.* In recent years still more attention 

* Kecorded and figured in Joum. Q. M. C, vol. viii., November 1903, 
p. 539, and vol. ix., April 1904, PI. 2 (15). For further notes on this species 
see also The Wild Fauna and Flora of the Royal Botanic Gardens, Kew, 
p. 20 (16). 



432 D. J. SCOURFIELD OX A NEW COPEPOD FOUND IN 

has been given to the subject owing to the endeavour to discover 
the life-histories of mosquitoes and other insects supposed to be 
connected with the dissemination of tropical diseases. Last year 
a very elaborate paper was published by Picado (8), in which 
he gives details of the facts previously elucidated, and of his 
own work on this subject in Costa Rica. It appears that no 
less than about 250 species of animals have been found living 
in this peculiar environment, 49 being new to science. They 
belong to almost all groups of Invertebrates, but naturally 
insects and their larvae predominate. The Amphibia are also 
represented. A very full account of this paper has been recently 
published by H. Scott in the Zoologist (12). 

When once this peculiar habitat had been pointed out, it was 
natural that somewhat similar situations should be searched, and 
records have indeed been made of animals found living in the 
pitchers of Pitcher-plants and Sarracenias, the holes occurring 
occasionally in bamboos, the tops of palm trees, and in various 
other places. 

It occurred to me that perhaps the little collections of water 
which are sometimes to be found in the hollows and crevices 
on the trunks and exposed roots of trees might possibly be 
inhabited by some member or members of the Entomostraca, 
the group in which I am more particularly interested. This 
proved to be the case ; at least I am now able to report that 
on several occasions I have found the minute Copepod about 
to be described in such little reservoirs of water on trees in 
Epping Forest. Up to the present it has been found nowhere 
else, and, on the other hand, I have never found any other 
species of Entomostraca in the same places. 

The new species evidently belongs to the Harpacticid genus 
Moravia T. and A. Scott, and I propose to call it M. arboricola 
on account of its tree-dwelling habit. 

The genus Moravia is very closely allied to the well-known 
genus Canthocamptus, and is, in fact, even now included in the 
latter by some authors. It was instituted by T. and A. Scott in 
1893 (14) for a species found in Loch Morar, in Scotland, which 
they named M. andevson-smithi, believing it to be new, but 
which subsequently proved to be identical with C anthocamptus 
brevipes Sars, described thirty years previously (11). A month 
or two later in the same year, 1893, Mrazek described as new 



WATER FROM HOLLOWS ON TREE TRUNKS. 433 

the same species, placing it with two others which were really 
new to science, in a new genus, Ophiocamptus, thus showing that 
he also recognised the necessity of separating Sars's C. brevipes 
-and closely allied forms from the old genus C anthocamptus (4). 

The characteristics of the genus Moraria are chiefly as 
follows : Body very elongated, almost vermiform. Rostrum 
broad. First antennae seven-jointed. First four pairs of feet 
with three-jointed outer and two-jointed inner branches. Inner 
branches of first pair of feet only a little shorter than the outer 
branches, with the basal rather longer than the terminal joint. 
Inner branches of the second, third, and fourth pairs of feet 
only a little longer than the first joint, or at most only as long 
as the first two joints of the outer branches. Furca well de- 
veloped, each branch tapering considerably from base to tip, and 
usually (? always) furnished with a strong longitudinal chitinous 
ridge on the dorsal surface. 

So far as I can ascertain, eight species of Moraria have hitherto 
been described and two others referred to, but not described. 
They are as follows : 

M. brevipes (G. 0. Sars), 1863 = C anthocamptus brevipes G. 0. 
Sars, 1863 (11); M. anderson-smithi T. and A. Scott, 
1893 (14) ; Ophiocamptus sarsi Mrazek, 1893 (4). 

M. mrdzeki T. Scott, 1903 (13), new name only = Ophio- 
camptus brevipes Mrazek, 1893 (4). 

M. poppei (Mrazek), 1893 (4) = 0. poppei Mrazek, 1893 (4). 

M. muscicola (Richters), 1900 (9) = 0. muscicola Richters, 
1900 (9). 

M. schmeili van Douwe, 1903 (3). 

M. mongolica (Daday), 1906 (1 and 2) = 0. mongolicus Daday, 
1906 (1 and 2). 

M. wolfi Richters, 1907 (10). 

M. quadrispinosa Richters, 1907 (10). 

M. sp. 1 Richters, 1907 (10). 

M. sp. 2 Richters, 1907 (10). 

Most, if not all, of the above have been found living in wet 
-or damp mosses ; some, in fact, have hitherto been found in no 
other situations. Only the first three have been found in the 
British Isles. 



434 D. J. SCOURFIELD ON A NEW COPEPOD FOUND IN 

Moraria arboricola sp. nov. 

Female. Body (fig. 1) long and vermiform, divided into nine 
free segments, the first being the longest and the sixth (first- 
abdominal) the second in length. Rostrum broad. Eye red or 
brownish red, moderately large as a rule, but rather variable in 
size and in outline. Dorsal plate on carapace rather variable 
in shape, usually more or less rectangular with rounded angles r 
slightly broader in front than behind. Posterior margins of all- 
segments smooth on dorsal surface. On ventral surface abdominal 
segments (fig. 16) armed as follows: 1st, with two widely 
separated groups of about five teeth ; 2nd, with a row of teeth 
from one-third to half width of segment, sometimes with central 
teeth missing, thus leaving two isolated groups; 3rd, with a row 
extending almost across segment ; 4th (last), with a row com- 
pletely across segment and a little way round sides, except for 
the slight interruption caused by the posterior median notch. 
Anal plate or operculum (see fig. 15) more or less semicircular^, 
with smooth but slightly wavy edge, and with faint dark and 
light bands radiating towards the edge, showing probably that 
the plate is very slightly corrugated. 

In the stage before the adult the edge of the anal plate is not 
smooth, but furnished with a few very minute teeth, widely but 
somewhat irregularly spaced (fig. 13). In the still earlier stages 
the teeth are rather larger (fig. 12). The presence of teeth on 
the anal plate in the young stages of M. brevipes, which also 
has smooth edges in the adult, has been noted by Mrazek (4). 

Branches of furca (figs. 14 and 15) moderately long and taper- 
ing considerably, with a prominent chitinous ridge on the dorsal 
surface, ending posteriorly in a blunt tooth from the base of 
which springs a spine directed upwards. Outer edges armed 
with two strong spines, the proximal with a minute accessory 
spine at its base. Inner edges with two curved rows of minute 
teeth, terminating dorsally in little teeth on the chitinous plate. 
Posterior edges with a row of teeth on the ventral surface, 
covering bases of terminal setae. Terminal setae usually quite 
smooth, three on each furcal lobe, inner very small, outer not 
quite half the length of the median, which again is about half 
the body length. The outer and median setae, especially the 
latter, somewhat bulbous at the base. 



WATER FROM HOLLOWS ON TREE TRUNKS. 435 

First antennae (fig. 2) rather short and seven-jointed, with the 
olfactory seta, on the fourth joint reaching only to about the 
middle of the last joint. Second antennae of the usual type 
with the accessory branch (fig. 3) very small, one-jointed, bearing 
three setae at the tip. First pair of feet (fig. 4) small, with 
three-jointed outer and two-jointed inner branches. Inner 
branch not quite so long as outer, with one of the two terminal 
setae extremely long and curved at the tip. Second, third, and 
fourth pairs of feet (fig. 6) very similar to one another with the 
three-jointed outer branches larger than in the feet of the first 
pair, but with the two-jointed inner branches smaller, being only 
a little longer than the basal joints of the outer branches. The 
second joints of the inner branches of the second and third pairs 
of feet carry three terminal spines, the corresponding joint of the 
fourth pair only two. Fifth feet (fig. 8) consisting of two joints, 
the basal being extended on the inner side considerably beyond 
the broadly ovate second joint. Inner part of basal joint armed 
with six spines somewhat flattened, with rounded tips of the 
type found in M. brevipes Sars, but not quite so broad or blunt. 
The fourth and fifth spines from the inner edge arise from a 
little sub-rectangular projection which has the appearance of a 
pseudo-joint. A finely pointed spine projecting outwards arises 
as usual from the lower corner of the outer edge of the joint. 
The second joint armed with four spines, the innermost being 
of the same type as those on the basal joint, and the other 
three being finely pointed and not flattened. The median of 
these three turns outwards across the outer spine. There is a 
little thorn on the inner edge of this joint just above the inner- 
most spine. None of the spines on the fifth feet are plumose, 
but a single barb usually occurs on the fifth and sixth from 
the inner edge, as indicated in fig. 8. Earlier stages of the fifth 
feet are shown in figs. 10 and 11. 

Eeceptaculum seminis (fig. 18), lying immediately behind and 
usually covered by the fifth feet, somewhat complicated in 
structure, consisting apparently of two lateral highly chitinised 
convoluted chambers or tubes and a median membranous or 
muscular cavity, the latter sometimes rhythmically contracted 
and expanded by two lateral muscles, thus forming for a time 
a kind of pulsating organ. 

Chitinous integument of body and furca almost everywhere 



436 D. J. SCOURFIELD ON A NEW C0PEP0D FOUND IN 

covered with minute pits only readily noticeable under a 1/1 2th in. 
objective (see figs. 14, 15, 16 and 17). Dorsal surface of most 
of the thoracic and abdominal segments with lines of excessively 
minute teeth arranged in various ways characteristic of the 
different segments, often giving the impression of a series of 
scales (fig. 17). 

Eggs much elongated while in the body, only one or two on 
either side, forming two lateral lines extending sometimes from 
the second free thoracic to the last abdominal segment. As no 
ovisac has yet been observed, it may be that the eggs are 
deposited upon extrusion and not carried about.* 

Length without terminal setae, l/50th in. to l/40th in. 

Male. Very similar to female in general appearance, but body 
divided into ten free segments, the first longest and the seventh 
to tenth next in length and sub-equal. Posterior margins of 
abdominal segments armed on ventral surface as follows : 1st, 
with two widely separated groups of two spines each situated 
on a slight prominence forming rudimentary sixth feet ; 2nd and 
3rd, with a row of teeth about half the width of the segment ; 
4th and 5th, with a row across whole width of segment. Anal 
plate as in female, also furcal lobes and terminal setae, except 
that the two little curved rows of teeth on the inner sides of 
the furca are not so well developed. The edge of the anal plate 
is toothed in the young stages as in the female. 

First antennae modified in the usual way with no very 
characteristic features. First four pairs of feet almost exactly 
as in female except that the inner branches of the second, third 
and fourth pairs are larger and specially modified as follows : 
2nd (fig. 20), with a thick slightly curved process (? enlarged 
spine) projecting downwards from the anterior face of the basal 
joint and probably forming with the second joint a pincer like 
apparatus; 3rd (fig. 21), with second joint carrying two strong 
terminal setae, one of which is about a third the length of the 
other and shaped like the blade of a knife, and the first joint 
bearing a very large trailing spine curved towards the base ; 
4th (fig. 7), with both joints leaf-like, the second having a 
curiously twisted little spine on the lower outer margin. Fifth 
feet (fig. 9) simpler than in female, the slightly extended part 
of the basal joint with only two short spines, the second joint 

* See note on p. 440. 



WATER FROM HOLLOWS ON TREE TRUNKS. 437 

of a more elongated and rectangular shape with a spine arising 
from near the base on the inner edge, and four spines from the 
distal edge, the third of which from the inner side turns outwards 
across the outer spine. None of the spines are of the flattened 
blunt type present on the fifth foot of the female. 

The spermatophore (fig. 19) is flask or retort-shaped with very 
thick walls, the outlet tube being embedded for a part of its 
length in a mass of cementing material.* 

Length without terminal setae, about l/50th in. 

As regards the habits of M. arboricola not very much can be 
said. They are not very good swimmers, their movements in the 
open water being best described, perhaps, as an active wriggling 
assisted by the beating of the feet rather than as true swimming 
produced chiefly by the action of the feet. On the whole they 
seem to prefer moving downwards more than upwards when free 
from support. They can, however, cling very strongly even to 
glass, and often in this way travel about the sides of the vessel in 
which they are kept. Very often I have found that they have 
clung to the inside of the pipette whilst being transferred from a 
bottle to the live-box. When placed in a watch-glass I have noticed 
on several occasions that a tap on the glass had the effect of suddenly 
stopping their movements just as if they were feigning death. 

As already mentioned, M. arboricola has only been found in 
little hollows on tree trunks in Epping Forest, and so far only 
in the Theydon Bois and High Beech districts, f The first 
specimens were found in 1904 near Theydon Bois, and since that 
date the species has been obtained many times either actually 
living in the water and sediment or developing out of the black 
earthy deposit taken from dry hollows and placed in water. It 
has happened on several occasions that no trace of the animals 
could be found in the first instance, but that after several weeks,. 

* This peculiar mass can be seen in the same relative position while the 
spermatophore is still within the body of the male. It seems therefore to 
be a constant character and not merely a temporary feature produced at 
the time of attachment to the female. 

t The fact that so many of the Epping Forest trees have been pollarded 
in bygone times has had the effect of largely increasing the number of 
cavities and hollows on their heads and trunks in which water can 
accumulate in wet weather, thus rendering the district a particularly 
favourable one for the study of the fauna and flora of such a peculiar 
environment. The systematic investigation of this fauna and flora is much 
to be desired, and could scarcely fail to vield valuable results. 



438 D. J. SCOURFIELD ON A NEW COPEPOD FOUND IN 

or even a month or two, specimens have begun to appear. From 
the fact that the females have not been observed carrying ovisacs * 
it seems possible that the eggs are dropped into the sediment to 
lie dormant for a time, or even to be dried up and so perhaps 
blown about by the wind. This might account for their distribu- 
tion from one tree to another, although it is very probable that 
insects, of which a number of forms occur in the same situations, 
may also be a means of dispersal. In this connection and also in 
relation to their peculiar habitat the wonderful vitality of the 
animals may play an important role. They seem capable of 
living for a very long time in quite small quantities of water 
and with scarcely any food. On one occasion specimens continued 
in evidence for four and a half years in a 3-in. x 1-in. glass tube 
in which the collection had been brought home. The tube con- 
tained nothing in the way of food, except the very innutritious- 
looking original sediment, and nothing was added during the 
whole time but a little clean water. Individual specimens, too, 
have been kept for months in very small tubes with only the 
merest trace of sediment and have remained perfectly active. 
Such powers of endurance must evidently be of the greatest 
value to them in their natural surroundings. 

Literature Referred to. 

1. Daday, E. von. Edesvizi mikroskopi allatok mongoliabol. 

Math. Termt. Ert., Vol. 24, 1906, pp. 34-77. 

2. Daday, E. von. Beitrage zur Kenntnis der Mikrofauna des 

Kossogol-Beckens in der Nordwestlichen Mongolei. Math. 
Nat. Berichte aus Ungarn, Vol. 26, 1913, pp. 274-360. 

3. Douwe, C. van. Zur Kenntniss der Sussuasser-Harpacticiden 

Deutschlands. Zool. Jahrbucher. A bt. fiir Systematize, etc., 
Vol. 18, 1903, pp. 383-400. 

4. Mrazek, A. Beitrag zur Kenntniss der Harpacticiden fauna 

des Siisswassers. Zool. Jahrbucher. Abt. f. Systematic, 
etc., Vol. 7, 1893. 

5. Muller, F. Descripgao do Elpidium bromeliarum crustaceo 

da familia dos Cythei icleos. Arch. Museu National do 
Rio de Janeiro, Vol. 4, 1879, pp. 27-34. 

6. Muller, F. Phryganiden-Studien. 3. Wasscrthiere in den 

Wipfeln des Waldes. Kosmos, Vol. 4, 1879, pp. 390 392. 

* See note on p. 440. 



WATER FROM HOLLOWS ON TREE TRUNKS. 439 

7. Muller, F. Wasserthiere in Baumwipfeln. Elpidium 

bromeliarum. Kosmos, Vol. 6, 1880, pp. 386-388. 

8. Picado, C. Les Bromeliacees epiphytes, considerees comme 

milieu biologique. Bull. Scientifique de la France et de 
la Belgique, Vol. 47, 1913, pp. 215-360. 

9. Richters, F. Bfitrage zur Kenntnis der Fauna der 

Umgegend von Frankfurt a. M., III. Ophiocamptus 
muscicola n. sp., ein moosbewohnender Copepode. Bericht 
der Senckenbergischen N aturforschenden Gesellschaft, 1900, 
pp. 36-39 (also further notes in the same publication, 
1902, pp. 6-7). 

10. Richters, F. Die Fauna der Moosrasen des Gaussbergs und 

einiger siidlicher Inseln. Deutsche Slid-polar Expedition, 
1901-1903, Vol. 9, 1907. 

11. Sars, G. O. Oversigt af de indenlandske Ferskvands Cope- 

poder. Vidensk.-Selsk. i Christiania Forhandl. for 1862 
(Aftr.), 1863, p. 24. 

12. Scott, H. The Fauna of "Reservoir-plants." Zoologist, 

Vol. 18, 1914, pp. 183-195. 

13. Scott, T. Some Observations on British Freshwater Har- 

pacticids. Annals and Magazine Nat. Hist., Series 7, 
Vol. 11, 1903, pp. 185-196/ 

14. Scott, T. and A. On some new or rare Scottish Entomo- 

straca. Annals and Magazine Nat. Hist., Series 6, 
Vol. 11, 1893, pp. 210-215. 

15. Scourfield, D. J. Synopsis of the known species of British 

Freshwater Entomostraca, Part II. and Part III. (Plate). 
Journal Quekett Micro. Club, Series 2, Vol. 8, 1903, 
p. 539, and Vol. 9, 1904, p. 44. 

16. Scourfield, D. J. The Wild Fauna and Flora of the Royal 

Botanic Gardens, Kew. Crustacea, Entomostraca. 
Bulletin of Miscellaneous Information, Additional Series V. 
(Royal Botanic Gardens, Kew), 1906, pp. 14-20. 

Explanation of Plates 24 and 25. 

Moraria arboricola sp. nov. 

Fig. 1. Dorsal view , x 200. 
,, 2. First antenna ? , x 700. 
,, 3. Accessory branch of second antenna 



55 
55 




440 D. J. SCOURFIELD ON A NEW COPEPOD. 

Fig. 4. First foot ? , x 6C0. 

5. Seta on inner angle of basal joint of first foot <$ . 

6. Fourth foot ?, x 600. 

7. Inner branch of fourth foot J 1 , x 1000. 
8. Fifth foot ?, x 1000. 

9. ,, S, x 700. 

10. young ? (antepenultimate stage). 

11. $ (penultimate stage). 

12. Anal plate, young (three stages before adult). 

13. (penultimate stage). 

14. Last abdominal segment and furca from side ?/x 700, 

15. ,, ,, dorsal view ? , x 700, 

16. 3 ,, segments ,, ventral view (some- 
what flattened and contracted), x 350. 

17. First and second abdominal segments, dorsal view ? y 
X 350. 

18. Receptaculum seminis $, x 900. 

19. Spermatophore, x 400. 

20. Inner branch of second foot $ (from left side), x 500. 

21. third <?, x 500. 



5> 

J) 
)) 
>> 

55 



55 



Note added April 1915. 

A single individual of M. arboricola has now been seen carrying 
an ovisac containing four eggs, the latter being almost perfect 
spheres l/500th inch in diameter. The ovisac itself was very 
delicate and soon became detached, and also separated into two 
parts, each containing two eggs, by the movements of the animal 
when lightly held in the live-box. 

Nauplii in various stages have also been seen. The earlier 
forms exhibit a somewhat elaborate structure on the back, con- 
sisting of three pairs of papillae with pointed tips lying between 
two strong lateral thorns. Whether this is characteristic of the 
species or not is unknown. 



Journ. Quekett Microscopical Club, Ser. 2, Vol. XII., N: 76, Ap 1915. 



Journ.Q.M 



Sep. 2 ai,P1.24. 




Scourfield del. ad 



-Newman lith. 







Jour- 



Ser.2 25. 






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Wrv^ 



!0 






(J 







. 



j'/fVl/Vi'Wi -YJCWW 























ScourfielddeLadnat. West,Newn u 

kria arborieola sp.nc 



441 



SOME DETAILS IN THE ANATOMY OF THE RAT-FLEA, 
CERATOPHYLLUS FASCIATUS BOSC. 

By Prof. E. A. Minchin, M.A., Hon. Ph.D., F.R.S. 

{Bead January 2Qth, 1915.) 

Plates 26-32. 

During the past five years I have been engaged, in collaboration 
with a friend, upon investigations, recently published,* into the 
development of the rat-trypanosome in its invertebrate host the 
rat-flea (Ceratophyllus fasciatus). In the course of this investi- 
gation we have dissected and examined some 1,700 fleas ; and 
although these dissections were not undertaken with the 
primary object of studying the anatomy of the flea, but only 
with the intention of extracting and examining those organs of 
the flea likely to contain stages of the trypanosome, it goes 
without saying that we have not pulled so many fleas to pieces 
without gaining some insight into the structure of the insect, 
and it seemed to me worth while to study some anatomical points 
of structure in more detail and in special preparations. Some 
parts of the flea are very interesting as regards their structural 
relations and make very beautiful microscopic preparations which 
can be mounted with very little trouble. I thought it might 
interest the members of the Club if I laid before them a brief 
account of some points of flea-anatomy seen by the way obiter 
visa, if I may use the expression, 

Before describing these observations, I wish it to be clearly 
understood that this paper does not pretend to give a complete 
anatomical description either of the flea as a whole or even of 
the systems of organs that are dealt with. There are many 
structural details which could only be made out by sections, and 
I have had no leisure for the task of section-cutting, always a 
difficult and laborious undertaking in the case of insects, on 
account of the toughness of the chitinous cuticle, which cannot 

* Minchin and Thomson, " The Rat-trypanosome, Trypanosoma lewisi, 
in its Relation to the Rat-flea, Ceratophyllus fasciatus" Quarterly 
Journal of Microscopical Science, Vol. LX., Part 4, 1915. 

Journ. Q. M. C, Series II. No. 76. 31 



442 E. A. MINCHIN ON SOME DETAILS IN THE ANATOMY OF 

be dissolved out. I do not propose to describe any details here 
which cannot be verified by an observer possessing a dissecting 
microscope * and a pair of mounted dissecting needles and a 
flea ! In fact the results obtained by me and set forth here are 
based entirely on what may be termed " needlework." 

Before proceeding to anatomical descriptions, I may give a 
brief account of the technique I have employed. The flea at 
liberty is, I need not say, an active and elusive insect. But 
when placed on the surface of water, he is perfectly helpless, and 
floats there without being able to escape and without drowning 
for at least twenty-four hours, provided there is no soap in the 
water ; if there is a trace of soap the cuticle of the flea is wetted 
and the insect sinks and is soon drowned. (This hint may be 
borne in mind as being often useful in the home.) 

Having therefore caught your flea, put it on the surface of 
some water and keep it until you can proceed further with your 
operations. An expeditious way of catching the flea is to get 
it to hop straight on to the surface of water. In doing this 
remember that a flea always hops by preference away from the 
source of light, never towards it. 

When it is desired to dissect the flea it should be gathered off 
the surface of the water with a fine forceps and placed in a drop 
of physiological salt-solution (0*75 gramme sodium chloride in 100 
cubic centimeters of distilled water) on an ordinary microscopical 
slide, which is then placed on the stage of the dissecting 
microscope. 

For the dissection I use two fine needles mounted in wooden 
handles. Each needle after fixing in the handle is ground down 
further on an ordinary hone. One of them is ground to a fine 
sharp point, the other to a flat cutting edge. For preparing the 
flat-edged needle, I first take a penknife and pare the extremity 
of the wooden handle on both sides so that it is shaped like an 
ordinary brad-awl. I then rub the needle down on the hone in two 
planes parallel to the two cuts made in the handle, checking the 
process under the dissecting microscope and trying to get a 
rounded cutting edge, not an edge which terminates in a straight 
line like an ordinary chisel. The object of paring the wooden 
handle is both to guide the hand when rubbing down the needle 

* I have used in all my work a Greenough binocular dissecting 
m'croscope made by Zeiss. 



THE RAT-FLEA, CERATOPHYLLUS FASCIATUS BOSC. 443 

on the hone, and also to distinguish the flat-edged needle from 
the pointed one. When dissecting I use the pointed needle in 
my left hand for holding the object, and the flat-edged needle in 
my right hand for cutting. The needles should be pushed far 
into the wooden handle, so that only a short length is free, other- 
wise the needle is too springy and is liable to snap under 
pressure. 

The flea was left in the drop of salt-solution, where it is kicking 
about violently and may succeed, if not watched, in getting out 
on to the slide and hopping off*. It is therefore best to begin by 
decapitating the flea. This can be done by holding it still with 
the pointed needle and snipping off the head with the flat-edged 
needle. The dissection can then be proceeded with in a manner 
free from haste or anxiety. 

I will describe now a method of making permanent preparations 
of the organs of the flea which I have found very useful. There 
is not a single detail of anatomy described in this paper which I 
could not demonstrate to a sceptic in my permanent preparations * 
at a moment's notice. Let us take the abdominal nervous system, 
for example. The complete nervous system of the flea consists, 
as in other insects, of the three sets of nerve-ganglia: (1) the 
cephalic ganglion -complex, or brain, situated in the head dorsal 
to the digestive tract (supra-oesophageal) ; (2) three pairs of 
thoracic ganglia, corresponding to the three thoracic segments : 
(3) a chain of abdominal ganglia extending into the abdomen. 
Parts (2) and (3) are ventral to the digestive tract and constitute 
a continuous chain of pairs of ganglia, but the two ganglia of any 
given pair are fused together so as to appear like a single ganglion- 
mass. Each pair of ganglia is connected with the pair next 
behind or in front by a pair of stout nerves, known as " connec- 
tives," and it can be plainly seen that these connectives remain 
distinct in each pair, and are not fused together like the ganglion- 
pairs (PI. 26). The first pair of thoracic ganglia is connected 
with the brain by a pair of peri-oesophageal connectives. From 
the ganglia are given off* nerves to the various organs of the body. 

It is almost impossible to dissect out the brain, and to study its 

structure and relations sections would be necessary. It is difficult, 

but by no means impossible, to dissect out the thoracic ganglia. 

Major Christophers, I. M.S., who worked for a time in my 

* These preparations are now the property of the Club. 



444 E. A. MINCHIN ON SOME DETAILS IN THE ANATOMY OF 

laboratory at the Lister Institute, made some beautiful dissections 
of the ventral nervous system of the flea, showing both thoracic 
and abdominal ganglia in continuity. On the other hand, it is by 
no means difficult to dissect out the abdominal chain in its whole 
length, up to and including the large metathoracic ganglia, the 
ganglia of the jumping legs. To do this the flea should be held by 
the thorax with the pointed needle, while with the flat -edged needle 
the abdominal segments are carefully detached and pulled off 
from behind forwards successively, until only the thoracic segments 
are left. If the operation has been successfully performed, and 
the abdominal segments together with the contained digestive 
and reproductive organs removed, the abdominal chain of ganglia 
will be seen proceeding from, and adhering to, the hindmost 
thoracic segment. With practice the complete severance of the 
abdomen and its organs from the thorax can be effected with one 
pull. 

Now take another slide and place on it a cover-slip (| inch 
square). Place the slide and cover-slip on the stage of the dis- 
secting microscope, put a quite small drop of salt-solution on the 
cover-slip, and transfer the thorax of the flea from the slide on 
which it was dissected to the small drop of fluid on the cover-slip, 
and there proceed with the dissection. The big metathoracic 
ganglion-mass can be seen quite plainly in the hindermost part 
of the thorax, with the abdominal chain of ganglia proceeding 
from it. With the needles the metathoracic ganglion must be 
carefully dissected out and set free from the thorax ; this operation 
is not at all difficult, though it requires both skill and practice to 
dissect out the first two thoracic ganglia as well, in unbroken 
continuity with the rest of the ganglionic chain. If during the 
dissection the cover-glass slips about on the slide, it can be fixed 
quite firmly by letting a tiny drop of distilled water run in between 
cover-glass and slide, but I avoid this as a rule, because it makes 
it difficult to get the cover-slip off later on. 

When the dissection has been completed, the fragments and 
debris of the thorax should be removed and cleaned up as much 
as possible, leaving the nervous system in the small drop of fluid 
on the cover -slip. Now the cover-slip must be lifted carefully off 
the slide and all superfluous moisture drained off it, so as to leave 
the nervous system stranded on the cover-slip, as near the centre 
as possible. The fluid can be drained off either by tilting the 



THE RAT- FLEA, CERATOPHYLLUS FASCIATUS BOSC. 445 

cover-glass and letting the salt-solution run off, or, if the nervous 
system shows a tendency to run off with the fluid, by holding the 
cover-glass flat and carefully mopping up all superfluity of fluid 
with a small piece of filter-paper. The object to be attained is to 
leave the specimen stranded on the cover-glass and to drain off as 
much of the salt-solution as possible, in order that by capillary 
attraction the object may be pressed against the cover-slip ; but 
on no account must the fluid be allowed to dry completely. When 
this has been done the cover-slip is inverted, so that the object is 
on its lower side ; and then it is dropped face downwards quite 
flat on to the surface of some fixative fluid. 

Various fixatives can be used, but I have nearly always made 
use of 5 per cent, sublimate-acetic that is to say, saturated 
solution of corrosive sublimate in distilled water, 95 volumes, 
mixed with glacial acetic acid, 5 volumes. When fixing the 
preparation some of the fixative is put into a large watch-glass 
or clock-glass and the cover-glass with the adherent object is 
dropped on to it and remains floating on the surface of the 
solution. In nine cases out of ten the object remains firmly 
adherent to the under side of the cover-glass, if one has hit the 
happy medium in draining off the fluid in which it was dissected 
out. If superfluity of the salt-solution remains, the object will 
come off; if it has been allowed to dry up altogether, the 
preparation is ruined. 

The cover-glass with the adherent organs can now be mani- 
pulated just as if it was a smear, lifting the cover-slip with an 
ordinary forceps and transferring it from one liquid to another. 
After the preparation has been fixed in the sublimate-acetic for 
some time, say from 10 minutes to an hour, it can be brought 
up through successive strengths of alcohol in watch-glasses 
(10 per cent., 30 per cent., 50 per cent, and 70 per cent.) to 
90 per cent, alcohol, in which it should be left for a longer time 
(preferably over night, or as long as is convenient) in order that 
the preparation may be well hardened and the corrosive sublimate 
thoroughly dissolved out. In the stronger alcohols the cover-slip 
will sink, but it rests on its corners on the rounded bottom of 
the watch-glass and there is no contact or pressure on the object, 
which of course is on the under side of the cover-slip. It is now 
apparent why square cover-slips must be used, since they rest on 
their corners and can be easily picked up with the forceps : 



446 E. A. MINCHIN ON SOME DETAILS IN THE ANATOMY OF 

round cover-slips would be in contact with tbe watch-glass round 
their whole edge, and be very troublesome to lift up with the 
forceps or in any other way. 

Sometimes the object comes away loose from the cover-slip in 
the sublimate-acetic. When this annoying event takes place,, 
put the cover-slip into a watch-glass and cover it with 30 per cent, 
alcohol; then draw up the object from the sublimate-acetic 
mixture with a glass pipette of sufficiently wide calibre and place 
it on the upper surface of the cover-slip in the alcohol. Then lift 
up the cover-slip carefully with a forceps, taking care the object 
does not float off the cover-slip to one side or the other, but 
remains stranded on the cover-slip again. Then drain off the 
alcohol, invert the cover-slip, and drop it face downwards into 
50 per cent, alcohol in another watch-glass. This time the 
rebellious object always sticks to the cover-slip. In all cases the 
cover-slips should be handled delicately while in the sublimate- 
acetic or in the weak alcohols, since a too violent jerk may 
dislodge them ; but I have never known an object to come loose 
after it has got so far as the 70 per cent, alcohol. 

I have described this method in full detail because I have 
found it extremely useful for making permanent preparations 
of dissections. In the flea, for example, it is very easy to dissect 
out and mount in this way the entire male reproductive system, 
from testes to penis, and so display every detail of it ; and since 
the preparation is adherent to the cover-slip, any powers of the 
microscope, even immersion lenses, can be focused on to it for 
study of minute details. The principle of the method is that 
cellular tissues, having been pressed firmly but gently against 
the glass by capillary attraction, adhere to the glass by their 
own stickiness ; and when the preparation has been well fixed 
and hardened, the coagulation of the albumins glues the organs 
so firmly that they cannot be detached without breaking 
them. Naturally this does not apply to chitinous organs, 
which are not wetted by water, and can never be made to stick 
in this way. 

The preparations, after having been fixed and hardened, can 
be mounted unstained, or can be stained first in any way desired.. 
Unstained preparations are best for showing internal details of 
the chitinous cuticle or skeleton ; stained preparations for 
showing the cellular structure of the tissues and soft parts ; the 



THE RAT-FLEA, CERATOPHYLLUS FASCIATUS BOSC. 447 

one method of preparation supplements the other. For staining 
an alcoholic stain is preferable, since prolonged soaking in watery 
stains might produce maceration and cause the object to become 
detached again from the cover-slip. I have always used Gren- 
adier's alcoholic borax-carmine, in which the objects are stained 
for about five minutes, and then transferred to acidulated alcohol 
(0*1 per cent, hydrochloric acid in 70 per cent, alcohol), in order 
to extract all the carmine stain from the cytoplasm of the cells 
and leave it only in the nuclei. If the stain be not thoroughly 
extracted in this way the preparation will be very opaque, and 
I find it best to leave the objects in the acidulated alcohol for about 
forty-eight hours, changing the fluid occasionally. I believe this 
method could be improved upon, and that Mayer's alcoholic 
paracarmine * would give a more transparent stain, and one 
more easily extracted. Some of the well-known haematoxylin 
mixtures would probably also give good results. 

The stained or unstained preparations are then finished off by 
passing them into absolute alcohol, then into oil of cloves or any 
other of the ordinary clearing reagents, and finally into Canada 
balsam. The cover- slips can be mounted over well-slides or 
preferably, in my opinion on ordinary slides, with the precau- 
tion of supporting the corners of the cover-slip on wax feet or in 
some other way, in order that the objects may run no risk of 
being crushed between slide and cover-slip. 

I will now proceed to set forth some of my observations on the 
anatomy of the flea, noting, as a preliminary, that all my state- 
ments apply to the common rat-flea, Ceratophyllus fasciatus y 
the only species I have dissected. Other species of flea may 
perhaps show slight differences in some points. 

It is also my pleasant duty, at this point, to express my warm 
thanks to Miss Mabel Rhodes, artist at the Lister Institute, for 
kindly executing the drawings of my dissections which accompany 
this paper. They were all drawn with the camera lucida from 
the actual preparations. 

I. The Abdominal Nervous System. 

The method of dissecting out the abdominal chain of nerve- 
ganglia has been described above. It is one of the easiest 

* For an account of these stains and how to prepare them see Bolles 
Lee's well-known Vade-mecum. 



448 E. A. MINCHIN ON SOME DETAILS IN THE ANATOMY OF 

dissections if one is content to get out only the large meta- 
thoracic ganglion-mass, in the thoracic series, and not to worry 
about the ganglia of the first two thoracic segments, which 
require very careful dissection. 

A remarkable feature of the abdominal nervous system is that 
it presents very marked differences in the two sexes of the flea. 
These sexual differences are seen at a glance in the two figures 
on PI. 26, which are drawn from two preparations to the same 
scale by means of a camera lucida. At the upper end of each 
figure we see the large metathoracic ganglion-mass, and at the 
lower end the large hindmost or terminal ganglion-complex from 
which nerves are given off to the genitalia. Between these two 
larger nerve-centres at the two extremities there is a series of 
smaller ganglia ; and it is easy to see that this series comprises 
seven ganglia in the male and only six in the female.* 

It is seen, then, that the male flea has one pair of ganglia 
more in its abdominal nervous system than the female. Is this 
an indication of superiority on the part of the male sex ? By 
no means, rather the contrary ! In the embryonic development 
of insects there are some ten or eleven pairs of abdominal ganglia, 
and in the ontogenetic development, or in the phylogenetic 
ovolution, of insects the tendency is for these ganglia to be 
concentrated by fusion which takes place progressively from 
behind forwards. In some of the Diptera the tsetse-fly, for 
example, and I believe in the common house-fly also the 
concentration of the nerve-ganglia has reached its maximum 
possible, since the whole ventral chain is concentrated into one 
large mass situated in the thorax, a mass which represents the 
three pairs of thoracic ganglia plus the whole abdominal chain, 
all telescoped forwards into one large ganglion-complex. In the 
flea, however, the process of concentration and specialisation has 
not gone so far, and is seen only at the hindmost end of the 

* This curious point was discovered by Major Christophers, in his 
dissections of fleas made in my laboratory. Previous to his work, I had 
counted the ganglia of a female flea that I was dissecting, and had noted 
that there were six small ganglia. Subsequently I made a mounted pre- 
paration of the abdominal chain of a male flea, and was surprised to 
observe seven small ganglia ; thinking I had made a mistake in my former 
observation, I looked up my old notes and altered " six " to " seven, ' 
never suspecting the sexual differences which were subsequently shown to 
exist. 



THE RAT- FLEA, CERATOPIIYLLUS F ASCI ATI'S BOSC. 449 

nervous system, in the large terminal ganglion-mass, which 
represents a fusion of the most posterior ganglia. The difference 
in the number of the abdominal ganglia in the two sexes of the 
flea shows, therefore, that in the female the concentration has 
gone one step farther than in the male, since only six abdominal 
ganglia remain free in the female, but seven in the male. The 
nervous system of the female has therefore reached one stage in 
evolution higher in the female than in the male. Similar 
differences between the sexes are known to occur also in other 
insects, especially in the Hymenoptera (the order which includes 
the bees, ants, and wasps), an order in which the superiority in 
intelligence and in the social virtues of the female over the male 
is very marked. 

Besides the difference in the number of ganglia, the nervous 
systems of the male and female flea differ also in the arrangement 
of the nerve-stems given off from the hindmost ganglion-mass. In 
the male two stout nerves are given off, which run on either side 
of the " corkscrew-organ'' (see p. 454), and are distributed mainly 
to the powerful muscles which work the penis. In the female, 
however, three pairs of moderately stout nerves are given off, 
which go to the genitalia, but I have not been able to trace their 
exact distribution. 

Comparing the two figures, it is seen that the male and female 
nervous systems are approximately of the same absolute length. 
Since, however, the female flea is considerably larger than the 
male, the nervous system of the female is relatively much 
the shorter, and does not extend so far into the abdomen as that 
of the male. Consequently the nervous system of the male is 
the easier to dissect out. 

As regards minuter details, the nerve-ganglia are seen to 
contain a number of nuclei, representing the ganglion-cells, 
which have a bilaterally symmetrical arrangement, showing that 
each ganglion-mass is a fusion of a pair of ganglia. The nerves 
which come off from the ganglia right and left contain small, 
elongated nuclei, which are the nuclei of the connective tissue- 
sheaths of the nerves. The connectives running between the 
successive abdominal ganglia contain no nuclei, but the stout 
connectives passing forwards from the metathoracic ganglion- 
mass contain elongated nuclei similar to those of the peripheral 
nerves. 



450 E. A. MINCHIN ON SOME DETAILS IN THE ANATOMY OF 

II. The Salivary Glands. 

Having occasion to dissect some flea-larvae, I was struck by 
the fact that the salivary glands of the larva differ greatly, both 
in size and in complication of parts, from those of the adult flea. 
I will begin with the adult, in which the glands are both smaller 
and simpler in structure. 

In the adult flea the salivary glands lie in the abdomen, right 
and left of the stomach, in the form of two tiny pouches on each 
side (PI. 27, B and C). Each pouch consists of large glandular 
cells, which tend to stain very opaquely and have large nuclei. 
The two pouches of each side give off each a short duct, and these 
two ducts unite into a long duct running forwards on the side of 
the body to the anterior thoracic region, where the two ducts from 
the two sides of the body unite into a common salivary duct, which 
runs forwards to open, doubtless, into the hypopharynx, as in 
other insects. The paired salivary ducts have a very character- 
istic appearance, being lined by a chitinous cuticle which shows 
internally a system of rather irregular transverse thickenings. 
This appearance is seen from the point where the ducts issue 
from the glands up to a short distance from the spot where the 
paired ducts unite to form the common salivary, duct ; the 
structure of the ducts recalls to some extent that of a tracheal 
tube, but the transverse thickenings are not so perfectly regular 
as in the tracheae. At the point of union of the right and left 
salivary ducts, however, there is a Y-piece in which the duct 
diminishes in calibre to about half, and has no transverse 
thickenings. External to the chitinous lining, the duct is 
covered by a delicate layer of flat epithelium, which does not 
show distinct cell-outlines, but has the appearance of a plas- 
modial or syncytial layer of protoplasm with scattered nuclei. 

The salivary gland of the adult flea, on account of its small 
size, is not so easy to dissect out ; the glands of the female are 
slightly larger than those of the male. On the other hand, the 
salivary glands of the larva, which are plainly visible through 
the body-wall of the living insect, are very easily dissected out. 
All that is necessary is to decapitate the larva in such a way as 
to cut off the first or first two thoracic segments, together with 
the head, and then to press with the flat of a dissecting needle 
gently along the body from behind forwards, so as to squeeze out 



THE RAT-FLEA, CERATOPHYLLUS FASCIATUS BOSC. 451 

the contents of the body-cavity through the cut end of the trunk. 
The salivary glands sometimes come out as soon as the flea is 
decapitated, without any such pressure, and it is easy to get 
them on to a cover-slip and fix them. 

Almost the only point in which the larval glands (PI. 27, A) 
resemble those of the adult is in the characteristic structure of 
the duct, which can be recognised immediately. Passing back 
along the duct (d.), we come to a thin- walled dilated sac or 
reservoir (r.), quite absent in the adult. Behind the duct a 
tubule begins, composed of lightly staining glandular cells. After 
a short course this tubule becomes continuous with the gland 
proper, which is composed of darkly staining glandular cells, and 
branches out into three lobes or diverticula, two of which run 
forward (l.a. 1 , l.a. 2 ) and one backward (l.p.) alongside of the 
digestive tract. All this arrangement of duct, reservoir, and 
gland is, of course, duplicated on each side of the body, right 
and left. 

Accompanying the larval salivary gland are two elongated 
pads or cushions of fat-body, which are very difficult to separate 
from the gland without damaging the glandular lobes. In the 
hinder of these pads of fat I found in many fleas a body which 
looked exceedingly like a parasitic cyst, for which I mistook it at 
first. Specimens mounted whole showed the " cyst " to be com- 
posed of large cells in the interior, showing a. tendency in the 
more advanced specimens to arrangement in longitudinal rows, 
and enveloped by a layer of flat epithelium at the surface. At 
its hinder end the " cyst " is prolonged into a delicate cord of cells 
which could be traced in some specimens a long way back. 
Further investigation showed, however, that when this " cyst " 
was present on one side of the body it was also present on the 
other side in exactly the same degree of development ; and further, 
that when the "cysts" were absent in the fat-body on the level 
of the salivary glands, they were to be found in other pads of fat- 
body situated farther back, on the level of the intestine right 
and left. Hence it was obvious that the supposed parasitic cysts 
were simply the genital rudiments, situated farther forward in 
the larvae of one sex than in the other. Whether it is the male, 
or the female, in which they are situated farther forward, I 
cannot say. 

The striking differences between the larval and adult flea in 



452 E. A. MINCHIN ON SOME DETAILS IN THE ANATOMY OF 

respect to the salivary glands must be related to the difference in 
their habits. The adult flea, I need not say, is a blood-sucker, 
and in blood-sucking insects generally the function of the salivary 
glands is believed to be that of producing a secretion which is 
mixed with the ingested blood and prevents it from coagulating. 
Incidentally the salivary glands of the adult flea, if crushed and 
examined, can be seen to contain many yeast-like bodies of several 
kinds, and it is supposed that it is these microbes which are 
responsible for the local irritation and itching caused by the 
puncture of the flea's proboscis. The flea-larva, on the other 
hand, is more or less omnivorous, but appears to feed principally 
on the faeces of the rat, as well as dirt and debris of all kinds. 
Consequently its salivary glands have a function in the insect's 
economy entirely different from that of the adult flea, assisting 
probably in the digestion of the food, and their larger size in the 
larva indicates a greater secretive activity than in the adult. 

III. The Male Reproductive Organs. 

The genitalia of the male flea exhibit a singular complication 
of parts and of their arrangement, but are nevertheless very easy 
to dissect out, and with a little care the entire reproductive system, 
from testes to penis, can be mounted as one preparation, in which 
every detail can be studied with the exception of those minuter 
points of structure which require sections for exact study. 

A general sketch of the various parts is given in Plate 28. 
All the details of this sketch have been drawn from mounted 
dissections with the camera lucida at a magnification of 150 
diameters, reduced in the reproduction by one-half. At the same 
time the relation of the various parts and their relative position 
in the body has been checked by sketches of the whole system, 
both of such parts of it as can be seen through the body-wall of 
the flea without dissection, and also as it is seen when the abdomen 
of the flea is freshly opened with the least possible disturbance of 
the organs. 

Most anteriorly are situated the two conspicuous testes (T , T.) 
with their ducts coming off from them, and shaped somewhat like 
a pear would be if the stalk (the duct) came off from its thicker 
end. The testes lie dorsal to the stomach, but vary to some 
extent both in size and arrangement. When the testes are of 
large size, as in the younger males, they lie one in front of the 



THE RAT-FLEA, CERATOPHYLLUS FASCIATUS BOSC. 453 

other, and then the duct of the testis lying more anteriorly runs 
straight back, while that of the testis situated more posteriorly is 
coiled. When the testes are smaller, as in the older, more 
exhausted males, they lie side by side and their ducts run straight 
back. 

When the testis is examined it is seen at once to consist of two 
parts, a dilated bladder-like portion of ovoid shape, at the base of 
which is a coiled tubular portion. The bladder-like portion 
appears to be the testis proper (T ), while the coiled tubular 
portion (ep. 1 ) recalls the structure in the human testis known as 
the epididymis, and may be known conveniently by this designa- 
tion. In one of my dissections I succeeded in uncoiling the 
epididymis forcibly, by pulling on the duct (ep. 2 ). It was then 
seen that the epididymis is a thin-walled tube, tilled with ripe 
spermatozoa ; consequently, from the point of view of function, 
the epididymis represents a vesicula seminalis, that is to say a 
receptacle for the storage of ripe sperm.* 

The calibre of the tubular epididymis narrows rapidly as it 
passes on into the duct, which may be called here, as in other 
animals, the vas deferens. The right and left vasa deferentia (v.d. 1 , 
v.d. 2 ) run back a little way and join to form the common vas 
deferens (v.d. 3 ), but it can be seen very easily that the union of 
the paired vasa deferentia is merely external and not internal, 
since the lumina, or internal cavities, of the two ducts remain 
quite distinct. 

The common vas deferens runs to a set of glandular structures 
which I regard as corresponding to a prostate gland, and consist- 
ing altogether of four blind tubular diverticula ; a median pair of 
short tubules, which maybe termed the median prostates (r.m.p.), 
and a much longer pair of lateral tubules,